51705016_Maple G4_Textbook Integrated_Term3

Example 11: Observe the pattern in these decimals and write the next three numbers in each. a) 0.12, 0.13, 0.14, _________, _________, _________ b) 2.00, 2.10, 2.20, _________, _________, _________ c) 8.5, 9.5, 10.5, _________, _________, _________ d) 23.31, 23.41, 23.51, _________, _________, _________ Solution: a) 0.12, 0.13, 0.14, 0.15, 0.16, 0.17 (increases by 1 hundredths) b) 2.00, 2.10, 2.20, 2.30, 2.40, 2.50 (increases by 1 tenths) c) 8.5, 9.5, 10.5, 11.5, 12.5, 13.5 (increases by ones) d) 23.31, 23.41, 23.51, 23.61, 23.71, 23.81 (increases by 1 tenths) Drill Time Concept 10.1: Conversion involving Fractions 1) Convert the following into fractions: a) 2.56 b) 14.02 c) 105.89 d) 52.60 e) 8.01 2) Convert the following into decimals: a) 2 b) 23 23 d) 73 e) 834 c) 1000 10 100 10 100 3) Write the following decimals in words: a) 73.5 b) 413.45 c) 0.73 d) 13.45 e) 1.87 4) Word problem The measures of some objects are given in the table. Height of a flag pole 9.50 m Side of a dining table 1.20 m Distance between the two cities 325.75 km Height of a plant 127.80 cm Write these lengths in words. Decimals 11

Chapter Money 11 Let Us Learn About • converting rupees to paise and vice versa. • problems involving conversion of money. • a dding and subtracting money with column method. • m ultiplying and dividing money. Concept 11.1: Conversion of Rupees and Paise Think Jasleen had some play money in the form of notes and coins. While playing, her friend gave her ` 10. Jasleen has to give paise for the amount her friend gave her. How many paise should Jasleen give her friend? Recall We have already learnt to identify currency and coins, conversion of rupees to paise and also that 1 ` = 100 p. Let us answer these to revise the concept of conversion of money. a) ` 62 = __________ paise b) 500 paise = ` __________ c) ` 28 = __________ paise d) 900 paise = ` __________ e) ` 76 = __________ paise f) 200 paise = ` __________ 12

& Remembering and Understanding We already know that to change rupees into paise we multiply the rupees by 100. For example, as ` 1 = 100 paise, ` 3 = 3 × 100 paise = 300 paise To convert an amount into paise we multiply the rupees given in the amount by 100 and add the product to the number of paise. To convert paise to rupee just add a decimal point two digits from the right. Let us see a few examples involving conversion between rupee and paise. Example 1: Convert ` 132.28 into paise. Solution: ` 132.28 = ` 132 + 28 p = ` 132 × 100 p + 28 p = 13200 p + 28 p = 13228 p Note: An easy way to convert rupees into paise is to remove the symbol (` and p)and the dot (.) between the rupees and the paise and write the number together. So, ` 132.28 = 13228 p. An amount of more than 100 paise, can be expressed in rupees and paise. To convert paise into rupees and paise, divide the number by 100. Write the quotient as rupees and remainder as paise. Example 2: Convert 24365 paise into rupees and paise. Solution: 24365 p = 24300 p + 65 p = ` 243 + 65 p = ` 243.65 Note: An easy way to convert ‘paise’ into ‘rupees’ and paise is to just put a dot (.) after two digits (ones and tens places) from the right and express it as `. TTh Th H T O So, 24365 = ` 243.65 2 4 36 5 a) Convert ` 477.95 to paise. Solve these c) Convert 44390 paise into b) C onvert ` 892.95 into rupees. paise. _________________________ _________________________ _________________________ Money 13

Application Now let us solve some examples involving conversion of money. Example 3: Sheeba has ` 223.57. How many paise does she have in all? Solution: Amount with Sheeba = ` 223.57 We know that, ` 1 = 100 paise. ` 223.57 = ` 223 + 57 p = 223 × 100 p + 57 p = (22300 + 57) p = 22357 p Hence, Sheeba has 22357 paise. Example 4: Anish has 2435 p and Beena has ` 23.75. Who has more money? Solution: Amount with Anish = 2435 p Amount with Beena = ` 23.75 To compare the money they have, both the amounts must be in the same units. So, we convert rupees to paise. ` 23.75 = ` 23 × 100 p + 75 p (Since ` 1 = 100 p.) = (2300 + 75) p = 2375 p Clearly, 2435 > 2375. Therefore, Anish has more money. Example 5: Ram has ` 374.50 and Chandu has ` 365.75 in their kiddy banks. Who has less amount and by how much? Solution: Amount with Ram = ` 374.50 Amount with Chandu = ` 365.75 Comparing the rupee part of the amounts, we get 365 < 374. So, ` 365.75 < ` 374.50. Therefore, Chandu has less money. The difference in their amounts = ` 374.50 – ` 365.75 = ` 8.75 Therefore, Chandu has ` 8.75 less than Ram. Higher Order Thinking Skills (H.O.T.S.) Let us see a few more examples of conversion of money. 14

Example 6: Complete the following by writing the number of different coins that can be used to pay ` 10 using different coins. 50 paise coins ` 10 1-rupee coins 2 - rupee coins 2-rupee coins and 1-rupee coins 5-rupee coins Solution: 20 50 paise coins ` 10 10 1-rupee coins 5 2-rupee coins 3 2-rupee coins and 4 1-rupee coins 2 5-rupee coins Example 7: Solution: Write two different ways in which you can pay ` 50. Combination 1: ` 50 = ` 20 + ` 20 + ` 10 Combination 2: ` 50 = ` 10 + ` 10 + ` 10 + ` 10 + ` 10 Concept 11.2: Add and Subtract Money with Conversion Think Jasleen went shopping with her elder sister. She bought some groceries for ` 110.50, vegetables for ` 105.50 and stationery for ` 40. They had ` 300. Do you know how much money was left with them after shopping? Money 15

Recall Recollect that we can add or subtract money just as we add or subtract numbers. 1) To find the total amount, we write one amount below the other. We see to it that the decimal points are exactly one below the other. We then add the amounts just as we add numbers. 2) To find the difference in amounts, we write the smaller amount below the bigger one. We see to it that the decimal points are exactly one below the other. We then subtract the smaller amount from the bigger one. Answer the following to revise the concept of addition and subtraction of money. a) ` 22.10 – ` 11.10 = ___________ b) ` 15.30 + ` 31.45 = ___________ c) ` 82.45 – ` 42.30 = __________ d) ` 15.30 – ` 5.20 = __________ e) ` 32 + ` 7.20 = ___________ & Remembering and Understanding To add or subtract a given amount of money, we follow the steps given below. Step 1: Express the given amounts in figures as decimal numbers. Step 2: Arrange the given amounts in a column. Place the decimal points exactly below one another. Step 3: Add or subtract the amounts as usual. Step 4: In the sum or difference so obtained, put the decimal point exactly below the other decimal points. Let us see some examples. b) ` 239.74 + ` 355.54 Example 8: Add: a) ` 547.38 + ` 130.83 Solution: a) ` p b) ` p 11 11 5 4 7.38 2 3 9.7 4 + 1 3 0.83 5 5.5 4 ` 6 7 8.21 +3 9 5.2 8 `5 16

Example 9: Subtract: a) ` 53354 − ` 24765 b) ` 866.95 − ` 492.58 Solution: a) ` b) ` p 12 12 14 4⁄ 2⁄ 2⁄ 4⁄ 1⁄4 7⁄ 1⁄6 8⁄ 1⁄5 8 6 6.9 5 53354 − 4 9 2.5 8 −24765 ` 28 5 8 9 ` 3 7 4.3 7 Application Let us now see a few real-life situations where addition and subtraction of money are used. Example 10: Anita saved ` 213.60, ` 105.30 and ` 305.45 in three months from her pocket money. How much did she save in all? Solution: Amount saved in the 1st month = ` 213.60 Amount saved in the 2nd month = + ` 105.30 Amount saved in the 3rd month = + ` 305.45 Therefore, the total amount saved in 3 months = ` 624.35 Example 11: Mrs. Gupta had ` 5000 with her. She spent ` 3520.50 for buying different food items. How much money is left with her? Solution: Amount with Mrs. Gupta = ` 5000.00 Amount spent on food items = – ` 3520.50 Therefore, the amount left with Mrs. Gupta = ` 1479.50 Higher Order Thinking Skills (H.O.T.S.) Let us see solve a few more real-life examples involving addition and subtraction of money. Example 12: Tanya had ` 525 and her friend Arpan had ` 330. They bought a gift for their brother’s birthday costing ` 495.75. How much amount is left with Tanya and Arpan so that they can continue their shopping? Solution: Amount Tanya had = ` 525 Amount Arpan had = ` 330 Total amount = ` 525 + ` 330 = ` 855 Money 17

Total amount = `p 855 . 00 The amount spent for the gift = – 495 . 75 359 . 25 Therefore, ` 359.25 is left with Tanya and Arpan. Example 13: The cost of three items are ` 125, ` 150 and ` 175. Suresh has only notes of ` 100. If he buys the three items, how many notes must he give the shopkeeper? Does he get any change? If yes, how much change does he get? Solution: Total cost of the three items = ` 125 + ` 150 + ` 175 = ` 450 The denomination of money Suresh has = ` 100 The nearest hundred, greater than the cost of the three items is ` 500. So, the number of notes that Suresh has to give the shopkeeper is 5. ` 450 < ` 500. So, Suresh gets change from the shopkeeper. The change he gets = ` 500 − ` 450 = ` 50 Concept 11.3: Multiply and Divide Money Think Jasleen knows the cost of one dairy milk chocolate and the cost of five biscuit packets. She could quickly find the cost of 10 dairy milk chocolates and 1 biscuit packet. Can you do such quick calculations? Recall Remember that we use multiplication to find cost of many items from the cost of one. Similarly, we use division to find the cost of one item from the cost of many. Multiplying or dividing an amount by a number is similar to the usual multiplication and division of numbers. Answer the following to revise the multiplication and division of numbers. a) 2356 × 10 = __________ b) 72 × 3 = ____________ 18

c) 200 ÷ 4 = ___________ d) 549 ÷ 3 = ___________ e) 621 × 2 = ___________ & Remembering and Understanding Let us understand how to multiply or divide the given amounts of money. When 1 or more items are of the same price, multiply the amount by the number of items to get the total amount. To find out the price of one item, divide the total amount by the number of items. Multiplying money To multiply an amount of money by a number, we follow these steps. Step 1: Write the amount in figures without the decimal point. Step 2: Multiply it by the given number, as we multiply any two numbers. Step 3: In the product, place the decimal point ( if the amount is a decimal number) after the second digit from the right. Example 14: Multiply: a) ` 14105 by 7 b) ` 312. 97 by 34 c) ` 506. 75 by 125 Solution: a) 2 3 b) 2 2 c) 11 1 `14105 13 2 33 2 ×7 ` 312 . 97 ` 506 . 75 `98735 × 34 × 125 1 11 111 1251 . 88 2533 . 75 + 9389 . 10 + 10135 . 00 ` 10640 . 98 + 50675 . 00 ` 63343 . 75 Dividing money To divide an amount by a number, we follow these steps. Step 1: Write the amount as the dividend and the number as the divisor. Money 19

Step 2: Carry out the division just as we divide any two numbers. Step 3: Place the decimal point in the quotient, immediately after dividing the rupees, that is, digits before the decimal point in the dividend. Example 15: Divide: a) ` 23415 by 7 b) ` 481.65 by 13 c) ` 543.40 by 110 Solution: a) 3345 ) )b) 37.05 c) 4.94 )7 23415 13 481.65 110 543.40 − 21↓ − 39↓ − 440↓ 24 91 1034 − 21 − 91 − 990 31 06 440 − 28 − 00 − 440 35 65 000 − 35 − 65 00 00 Application Let us solve a few real-life examples involving multiplication and division of money. Example 16: A textbook of class 4 costs ` 75.20. What is the `p cost of 35 such textbooks? 1 Solution: Cost of one textbook = ` 75. 20 21 Cost of 35 such textbooks = ` 75. 20 × 35 75 . 20 Therefore, the cost of 35 textbooks is ` 2632. × 35 11 376 00 + 22 5 6 00 `2 6 3 2 . 0 0 Example 17: 19 cakes cost ` 332.50. What is the cost of 1 cake? 17.50 Solution: Cost of 19 cakes = ` 332.50 Cost of 1 cake = ` 332.50 ÷ 19 )19 332.50 Therefore, the cost of 1 cake is ` 17. 50. − 19 ↓ 142 − 133 95 − 95 00 20

Higher Order Thinking Skills (H.O.T.S.) Let us see a few more examples involving multiplication and division of money. Example 18: Multiply the sum of ` 2682 and ` 2296 by 10 . Solution: The sum of ` 2682 and ` 2296 is ` 2682 + ` 2296. `` 1 2682 4978 +2296 × 10 `4 9 7 8 0 4978 Therefore, the sum multiplied by 10 = 4978 × 10 = ` 49780. Example 19: A bag has one bundle of ` 50 notes and one bundle of ` 20 notes. It also has two bundles of ` 10 notes and one bundle of ` 5 notes. What is the total amount of money in the bag? [Note: Each bundle consists of 100 notes.] Solution: Amount in the bundle of ` 50 = 100 × ` 50 (1 bundle) = ` 5000 Amount in the bundle of ` 20 = ` 20 × 100 (1 bundle) = ` 2000 Amount in two bundles of ` 10 = ` 10 × 200 (2 bundles) = ` 2000 Amount in the bundle of ` 5 = ` 5 × 100 (1 bunTdrlea) i=n` 5M00y Brain Total money = ` 5000 + ` 2000 + ` 2000 + ` 500 = ` 9500 Therefore, the total amount of money in the bag is ` 9500. Drill Time Concept 11.1: Conversion of Rupees and Paise 1) Convert the following to paise. a) ` 632.18 b) ` 952.74 c) ` 231.48 d) ` 537.58 e) ` 724.80 e) 78654 2) Convert paise to rupees. a) 52865 b) 64287 c) 13495 d) 34567 Money 21

3) Word problems a) Rehmat has ` 892.64. How many paise does he have in all? b) Andrews has 56700 paise. How much money does he have in all? Express your answer in rupees. Concept 11.2: Add and Subtract Money with Conversion 4) Add: a) ` 875.62 + ` 964.98 b) ` 3467.45 + ` 2356. 50 c) 25382 p + 65237 p d) ` 456.23 + ` 123.75 e) ` 279.50 + ` 642.90 5) Subtract: a) ` 132.75 – ` 112.90 b) 85732 p – 23784 p c) ` 578.14 – ` 345.89 d) ` 456.72 – ` 234.34 e) ` 784.50 – ` 234.25 6) Word problems a) Rosy has ` 451.20 and Chetan has ` 495.35 in their piggy banks. Who has more amount and by how much? b) Shane spent ` 213.60, ` 105.30 and ` 305.45 in three months. How much did he spend in all? Concept 11.3: Multiply and Divide Money 7) Multiply: a) ` 152.45 × 5 b) 27510 p × 2 c) ` 315.50 × 10 d) ` 113.50 × 15 e) ` 115.50 × 35 8) Divide: a) ` 126.12 ÷ 3 b) 22347 p ÷ 9 c) ` 111.44 ÷ 7 d) ` 121.77 ÷ 7 e) ` 824.40 ÷ 8 9) Word problems a) A packet of chips costs ` 24.40. How much will 5 such packets cost? b) A football costs ` 159.99. What is the cost of 26 such footballs? 22

Chapter Measurements 12 Let Us Learn About • relation between units of length, weight and capacity. • converting smaller units to larger units. • multiplying and dividing length, weight and capacity. Concept 12.1: Multiply and Divide Lengths, Weights and Capacities Think Jasleen had some guests visiting her place. Jasleen’s mother asked her to pour juice from three bottles, each of 1.5 litres, into 15 glasses. What was the total quantity of juice and how much juice was poured in each glass? Recall Let us revise the basic concepts of measurements, their units and the different operations involving measurements. Length: kilometre, centimetre, millimetre Weight: kilogram, gram, milligram Capacity: litre, millilitre Solve the following problems based on addition and subtraction of lengths, weights and capacities. 23

a) 560 m 65 cm – 230 m 55 cm = ___________ b) 250 g + 2 kg 500 g = ___________ c) 240 m 22 cm – 220 m 20 cm = ___________ d) 5 ℓ 250 mℓ + 4 ℓ 250 mℓ = ___________ e) 745 km 45 m – 434 km 15 m = ___________ & Remembering and Understanding To convert measures from a larger unit to a smaller unit, we multiply. To convert measures from a smaller unit to a larger unit, we divide. Let us understand the relation between the different units of length, weight and capacity in detail. Relation between units of length, weight and capacity Larger unit – Smaller unit Smaller unit – Larger unit Length 1m= 1 km 1000 1 km = 1000 m 1 m = 100 cm 1 cm = 1 m 100 1 cm = 10 mm 1 mm = 1 cm 10 1 g = 1000 mg 1 kg = 1000 g Weight 1 mg = 1 g 1 litre = 1000 mℓ Capacity 1000 1g= 1 kg 1000 1 mℓ = 1 ℓ 1000 1 kilolitre = 1000 litres 1 1 ℓ = 1000 kℓ 24

Conversion of smaller units to larger units Let us understand conversions through a few examples. Example 1: Convert the following: a) 5000 m to km b) 8000 g to kg c) 2000 mℓ to ℓ Solution: Solved Solve these a) C onversion of m into km 9000 m = ________________ km 5000 m = _____________ km 4000 g = ______________ kg 1000 m = 1 km So, 5000 m = 5000 ÷ 1000 m 3000 mℓ = ______________ ℓ = 5 km 5000 m = 5 km b) C onversion of g into kg 8000 g = _____________ kg 1000 g = 1 kg So, 8000 g = 8000 ÷ 1000 g = 8 kg c) C onversion of mℓ into ℓ 2000 mℓ = _____________ ℓ 1000 mℓ = 1 ℓ So, 2000 mℓ = 2000 ÷ 1000 mℓ =2ℓ Multiply and divide length, weight and capacity Interestingly, multiplication and division of lengths, weights and capacities are similar to that of usual numbers. Let us see a few examples. Example 2: Solve: b) 18 km 361 m × 19 c) 7 ℓ 260 mℓ × 37 a) 65 kg 345 g × 28 Measurements 25

Solution: a) 65 kg 345 g × 28 b) 18 km 361 m × 19 c) 7  260 m× 37 km m kg g ℓ mℓ 1 1 34 1 42 345 65 28 73 5 14 × 760 18 361 7 260 1 900 522 660 × 19 × 37 +1 3 0 6 1829 1 1 165 249 50 820 + 183 610 + 217 800 348 859 268 620 Example 3: Solve: a) 15 kg 183 g ÷ 21 b) 3 km 84 m ÷ 12 c) 5 ℓ 882 mℓ ÷ 17 a) 15 kg 183 g ÷ 21 b) 3 km 84 m ÷ 12 c) 5 ℓ 882 mℓ ÷ 17 15 kg 183 g 3 km 84 m 5 ℓ 882 mℓ = 15 × 1000 g + 183 g = 3 × 1000 m + 84 m = 5 × 1000 mℓ + 882 mℓ = 15183 g = 3084 m = 5882 mℓ 346 723 257 )17 5882 )21 15183 )12 3084 − 51 − 14 7 − 24 048 068 078 − 068 − 042 − 060 0063 0084 0102 − 0102 − 0063 − 0084 0000 0000 0 15 kg183 g ÷ 21 = 723 g 3 km 84 m ÷ 12 = 257 m 5 ℓ 882 mℓ ÷ 17 = 346 mℓ 26

Application Let us solve a few examples based on multiplication and division of length, weight and capacity. Example 4: The distance between two post offices A and B is 58 km 360 m. What is the total distance travelled in four round trips between A and B? Solution: The distance between two post offices A and B is 58 km 360 m. Four round trips = 4 times from A to B and 4 times from B to A = 8 times the distance between A and B Therefore, the total distance travelled in four round trips = 58 km 360 m × 8 = 466 km 880 m Example 5: Mrs. Rani has 2 kg of coffee powder. She wants to put it into smaller packets of 25 g each. How many packets will she need? Solution: Weight of coffee powder Mrs. Rani has = 2 kg 1 kg = 1000 g 2 kg = 2 × 1000 g = 2000 g Weight of one small packet = 25 g Therefore, the number of packets she needs = 2000 g ÷ 25 g = 80 Example 6: Rahul has a can of 6112 mℓ juice. If he pours it equally in 16 glasses, what is the quantity of juice in each glass? Solution: Quantity of juice in full can = 6112 mℓ Number of glasses into which the juice is poured = 16 Quantity of juice in each glass = 6112 mℓ ÷ 16 = 382 mℓ Therefore, each glass contains 382 ml of juice. Measurements 27

Higher Order Thinking Skills (H.O.T.S.) Sometimes, we have to use more than one mathematical operation to measure things. Consider these examples. Example 7: 185 kg sugar costing ` 444 is packed in paper bags. Each bag can hold 5 kg of sugar. Find the number of bags needed to pack all the sugar. Also, find the cost of each bag. Solution: Weight of sugar = 185 kg Weight of sugar in the paper bag = 5 kg Number of paper bags needed = 185 kg ÷ 5 kg = 37 Therefore, 37 paper bags of 5 kg sugar each can be made. Cost of 37 bags of sugar = ` 444 Cost of each bag = ` 444 ÷ 37 = ` 12 Therefore, 185 kg sugar can be packed into 37 bags costing ` 12 each. Example 8: A container can hold 13 ℓ 625 mℓ of milk. What is the capacity of 15 such containers? Give your answer in mℓ. Solution: Capacity of one container = 13 ℓ 625 mℓ Capacity of 15 such containers = 13 ℓ 625 mℓ × 15 = 204 ℓ 375 mℓ 1 litre = 1000 mℓ 204 ℓ = 204 × 1000 mℓ = 204000 mℓ 204 ℓ 375 mℓ = 204000 mℓ+ 375 mℓ = 204375 mℓ Therefore, the capacity of 15 cans is 204375 mℓ. Example 9: The distance between two places is 4520 km. Ratan travelled a fourth of the distance by bus paying ` 12 per km. As the bus failed, he hired a car and travelled three-fourths of the distance by paying ` 20 per km. What amount did he spend on travelling? Solution: Total distance = 4520 km 1 of the distance = 1 × 4520 km = 1130 km 4 4 Distance travelled by bus = 1130 km 28

Ratan travelled 1130 km by bus. Cost of ticket per km = ` 12 Cost of ticket for 1130 km = 1130 × ` 12 = ` 13560 Fraction of distance travelled by car = 3 4 Actual distance travelled by car = 3 × 4520 km 4 = 3 × 1130 km = 3390 km Cost of travelling by car per km = ` 20 Cost of travelling 3390 km = 3390 × ` 20 = ` 67800 Total amount spent by Ratan on travelling = ` 13560 + ` 67800 = ` 81360 Drill Time Concept 12.1: Multiply and Divide Lengths, Weights and Capacities 1) Convert: a) 2000 cm to m b) 5000 g to kg c) 5000 m to km d) 8000 mℓ to ℓ 2) Multiply: a) 85 kg 145 g ×10 b) 5 ℓ 225 mℓ × 65 c) 7 m 450 cm × 25 d) 5 km 150 cm × 12 3) Divide: a) 34 kg 450 g by 6 b) 50 ℓ 225 mℓ by 5 c) 17 m 85 cm by 9 d) 42 kg 420 g by 7 Measurements 29

Chapter Data Handling 13 Let Us Learn About • reading and interpreting bar graphs. • d rawing bar graphs based on the given data. Concept 13.1: Bar Graphs Think Jasleen attended a fruit festival conducted for a week in her school. She was asked to give a report on the sale of different fruits per day in the form of a graph. Till then Jasleen only knew how to represent the data as a pictograph. She wanted to find an easier and simpler way of representation. How do you think Jasleen would have given the report? Recall Recall these points: • The information collected for a specific purpose is called data. • The information given as numbers is called numerical data. • The information shown in the form of pictures is called a pictograph. 30

We have already learnt about pictographs. Let us recall them through the following. Let us recall the pictographs through the following example. The favourite sports of Class 4 students are given. Read the pictograph and answer the questions. Key: 1 = 6 students Favourite Sports of Class 4 Students Volleyball Cricket Basketball Kabaddi Football a) The most favourite sports of Class 4 students is _____________. b) The least favourite sports of Class 4 students is _____________. c) The number of students who like to play basketball is___________. d) The number of students who like to play football is _____________. e) The number of students who like to play kabaddi is _____________. Data Handling 31

& Remembering and Understanding While drawing pictographs, we choose a relevant picture to represent the given data. If the data is large, it is tedious and time consuming to draw a pictograph. An easier way of representing data is the bar graph. It uses rectangular bars of the same width. These bars can be a drawn either horizontally or vertically. Bar graphs are drawn on a graph paper. A suitable title is given for the bar graph. Let us understand how to read and interpret bar graphs. Example 1: The marks scored by Kamala in a monthly test are represented using a bar graph as given. Understand the graph and answer the questions that follow. Scale: X-axis: 1 cm = 1 subject; Y-axis: 1 cm = 5 marks Kamala’s Performance in a Monthly Test Marks Scored English Maths Science Social Music Hindi Studies Subjects 32

a) What is the title of the graph? b) In which subject did Kamala perform the best? c) In which subject does Kamala need to improve? d) What are Kamala’s total marks? Solution: a) The title of the graph is “Kamala’s Performance in a Monthly Test”. b) The height of the bar representing Maths is maximum. It means that, Kamala performed the best in Maths. c) The height of the bar representing Social Studies is the minimum. Example 2: So, Kamala needs to improve in Social Studies. d) Kamala’s total marks are 35 + 47 + 42 + 28 + 32 + 40 = 224 Information about a primary school is represented in the form of a bar graph as shown. Observe the graph carefully and answer the questions that follow. Scale: X-axis: 1 cm = 1 class; Y-axis: 1 cm = 5 students Strength of Primary School School Class strength Class Data Handling 33

a) What is the total strength of all the 5 classes? b) Which class has the least strength? c) Which class has the greatest strength? d) What is the title of the graph? Solution: a) Total strength is 42 + 36 + 38 + 43 + 45 = 204 b) Class 2 c) Class 5 d) Strength of a Primary School Application We have learnt how to read and interpret bar graphs. Now, let us learn to draw a bar graph. Steps to draw a bar graph: Step 1: Draw one horizontal line and another vertical line, called the axes. They meet at a point called the origin. Step 2: Take a suitable scale such as 1 cm = 5 units. Step 3: On the X-axis, show the items of the data and on the Y-axis show their values. Step 4: Draw bars of equal width on the X-axis. The heights of the rectangles represent the values of the data which are given on the Y- axis. Step 5: Give a relevant title to the bar graph. Let us understand this through an example. Example 3: The following pictograph shows the number of scooters manufactured by a factory in a week. Complete the pictograph. Then draw a bar graph for the same data. Key: 1 = 5 scooters 34

Weekday Scooters manufactured in a week Number of Monday scooters Tuesday Wednesday Thursday Friday Saturday Solution: Total Step 1: Let us follow these steps to draw a bar graph. Step 2: Count the number of pictures in the pictograph. Complete the table by writing the product of the number of pictures and the number of scooters per key. Take a graph paper and draw the X and Y axes meeting each other at one corner as shown. Data Handling 35

Step 3: Choose a suitable scale. Since the maximum number of scooters is 30 and the minimum is 10, we can take the scale as 1 cm = 5 scooters. Mark weekdays on the X-axis as 1 cm = 1 weekday. Mark the number of scooters manufactured on the Y-axis from 0 to 35. Number of scooters manufactured Mon Tues Wed Thurs Fri Sat Weekdays 36

Step 4: On the X-axis, mark 30, 15, 20, 25, 20 and 10 against the Y-axis as shown. We can plot these points two points apart. Number of scooters manufactured Step 5: Monday Tuesday Wednesday Thursday Friday Saturday Weekdays Draw vertical rectangular bars from these points for each weekday on the X-axis. Give a suitable title to the graph. Weekly Manufacturing of Scooters Number of scooters manufactured Monday Tuesday Wednesday Thursday Friday Saturday Weekdays Data Handling 37

We can draw the same graph using horizontal bars by interchanging the values on X and Y axes. Weekly Manufacturing of Scooters Weekdays Number of scooters manufactured Example 4: The number of roses sold during a month in Roopa’s shop is given in the table Week Number of roses sold 1st week 148 2nd week 165 3rd week 130 4th week 172 Represent the data in a bar graph. 38

Solution: Scale: X-axis: 1 cm = 1 week;Y-axis: 1 cm = 20 roses Roses sold Weeks Higher Order Thinking Skills (H.O.T.S.) Train My Brain Consider a few real-life examples where we represent data using a bar graph. Example 5: In 2010, the heights of Ramu, Somu, Radha and Swetha were noted as 130 cm, 125 cm, 115 cm and 120 cm respectively. After two years, their heights were again noted as 140 cm, 132 cm, 124 cm and 128 cm respectively. Draw a bar graph to represent the data and answer the questions that follow. a) Who was the tallest among the friends in 2010? b) Who was the shortest among them during 2012? c) How much taller was Ramu than Somu in 2010? d) Whose height has increased the maximum in 2 years? Data Handling 39

e) A rrange the children’s heights in 2010 in ascending order and their heights in Solution: 2012 in descending order. Name Height in 2010 Height in 2012 Ramu 130 cm 140 cm Somu 125 cm 132 cm Radha 115 cm 124 cm Swetha 120 cm 128 cm Scale: On X-axis: 2 cm = 1 student On Y-axis: 1 cm = 20 cm Comparison of Heights Height (in cm) Names of children 40

a) A s the bar for Ramu’s height in 2010 is the highest, Ramu is the tallest among the children. b) R adha is the shortest among them in 2012. (Shortest bar in 2012). c) Ramu is 5 cm (130 – 125) taller than Somu. d) Increase in the heights of the children in the two years: Ramu: (140 – 130) cm = 10 cm S omu: (132 – 125) cm = 7 cm Radha: (124 – 115) cm = 9 cm Swetha: (128 – 120) cm = 8 cm 7 cm < 8 cm < 9 cm < 10 cm Therefore, Ramu’s height increased the maximum in 2 years. e) Heights of the children in 2010: 130 cm, 125 cm, 115 cm, 120 cm Ascending order: 115 cm, 120 cm, 125 cm, 130 cm Heights of the children in 2012: 140 cm, 132 cm, 124 cm, 128 cm Descending order: 140 cm, 132 cm, 128 cm, 124 cm Example 6: The weights of four children are noted in 2014 and 2016 as given. Draw a bar graph and answer the questions that follow. Name Weight in 2014 Weight in 2016 Ram 30 kg 34 kg Shyam 34 kg 32 kg Reema 28 kg 31 kg Seema 29 kg 31 kg a) Who weighed the most in 2014 and 2016? b) Whose weight has decreased in 2016 from 2014? c) Name the two children who were of the same weight in 2016. d) Whose weight in 2014 is the same as that of another child in 2016? Data Handling 41

e) W rite the weights of the children in 2014 in descending order and their Solution: weights in 2016 in ascending order. Scale: O n X-axis: 2 cm = 1 student; Y-axis: 1 cm = 5 kg Comparison of Weights Comparison of Weights Weights (in kg) Ram Shyam Reema Seema Names of children a) Shyam was the heaviest in 2014 and Ram was the heaviest in 2016. b) Shyam’s weight decreased in 2016 from 2014. c) Reema and Seema are of the same weight in 2016. d) Shyam’s weight in 2014 is equal to Ram’s weight in 2016. e) Weights in 2014: 30 kg, 34 kg, 28 kg, 29 kg Descending order: 34 kg, 30 kg, 29 kg, 28 kg Weights in 2016: 34 kg, 32 kg, 31 kg and 31 kg Ascending order: 31 kg, 31 kg, 32 kg, 34 kg 42

Drill Time Concept 13.1: Bar Graphs 1) The score of students in an essay writing competition are given in the table. Draw a bar graph. Subject Marks scored Piyush 65 Suman 72 Vaishnavi 82 Pooja 93 2) The table shows the marks secured by Rajeev in Test 1 and Test 2. Subject Marks in Test 1 Marks in Test 2 Hindi 65 68 English 78 80 60 85 Mathematics 88 80 Science 54 65 Social Studies Compare his performance in the two tests by drawing a bar graph and answer the questions that follow. a) Find Rajeev’s total marks in Test 1 and Test 2 separately. b) In which of the two tests did he perform well with respect to Mathematics? c) In which subject(s) has he improved from Test 1 to Test 2? d) In which of the two tests has Rajeev got less marks? 3) The approximate monthly attendance of Grade 4 is shown in the pictograph given. Draw a bar graph and answer the questions that follow. Data Handling 43

Month Attendance June July August September October November Key: 1 = 10 students a) In which month is the attendance maximum? b) In which month is the attendance minimum? c) In which months is the attendance less than 45? 44





EVS-I (SCIENCE) TERM 3

Contents 4Class 14 Fuels����������������������������������������������������������������������������������������������������������������������������� 1 15 Ways of Communication �������������������������������������������������������������������������������������������� 5 16 Force and Work ��������������������������������������������������������������������������������������������������������� 11 17 Forms of Energy��������������������������������������������������������������������������������������������������������� 15 Inside the Lab – C ������������������������������������������������������������������������������������������������������������ 19 Activity C1: Building a Shelter Activity C2: Power of Solar Energy

Lesson Fuels 14 Let Us Learn About R fuels and their types. u motor fuels. a ways to save fuel. h renewable and non-renewable fuels. Think car We get energy to work from the food we eat. Look at the given pictures. Where do these vehicles get the energy to run? Is the source of energy the same? cycle rickshaw Remembering FUELS We have learnt that we get the energy to work from food. Vehicles get energy from fuels. A fuel is a material which provides energy to move or work. We use different types of fuels in our day-to-day life. Let us learn about different types of fuels. 1

TYPES OF FUELS Fuels can be in solid, liquid or gaseous form. 1) Solid fuels: Firewood, cow, dung cakes and coal are examples of solid fuels. 2) Liquid fuels: Petrol, diesel, kerosene and LPG are some liquid fuels. 3) Gaseous fuel: Coal gas, natural gas, LPG cylinder coal Compressed Natural Gas (CNG) are examples of gaseous fuels. We have seen fuels and their types. But where do these fuels come from? Most of the fuels we use are present in nature. Let us learn more about some natural fuels. FOSSIL FUELS Some fuels are found in the deeper layers of soil. They are a mine formed by the decay of dead organisms. When dead plants and animals get covered by heavy layers of soil, they change into fuels. These fuels are called fossil fuels. Formation of fossil fuels takes thousands of years. Example: petroleum (crude oil), coal and natural gas Fossil fuels are dug out from under the ground through mining. A mine is a hole or tunnel dug into the ground to take these raw fuels out. We make fuels like petrol, diesel, kerosene and LPG from petroleum. We use fuels for various purposes like cooking, transport and running machines in factories. 1) For domestic use, we use wood, coal, kerosene, cow dung cakes and LPG. 2) We use coal, diesel and petrol for road, sea and air transport vehicles. 3) Coal and natural gas are used in factories. Understanding The fuels used to run vehicles are called motor fuels. Motor fuels give energy to the vehicles to run. From where do we get the motor fuels for our use? Have you seen a petrol pump? We get the motor fuels from these pumps or fuel stations. petrol pump 2

Have you seen different coloured nozzles at a petrol pump? What do these colours mean? There are different types of motor fuels for which there are different coloured nozzles at the petrol pump. Find out which colour means which fuel. The following are some motor fuels: 1) Gasoline or petrol is the most common fuel used in cars and two-wheelers today. 2) Diesel is widely used in trucks, boats, buses and so on. 3) CNG is used to run cars, auto rickshaws or buses. 4) LPG can be used in certain vehicles. It is also used at our homes for cooking. What about other vehicles like trains, boats and aeroplanes? • Trains run on diesel or electricity. • Boats and ships with power engines mostly use diesel as a fuel. • Aeroplanes use petroleum fuels. Application The number of vehicles is increasing day by day. They all need fuel to run. Fuels are limited in supply and will one day be over. So, we need to use fuels carefully without wasting them. The different ways in which we can save fuels are: 1) switching off vehicles at signals. 2) getting our vehicles repaired regularly. 3) not using vehicles for walkable distances. 4) using public transport vehicles like buses. By taking these small measures, we can save a lot of fuel every day. Do you have a vehicle at your home? Do you go with parents to the petrol pump to fill petrol in it? Do you know how much a litre of petrol or diesel cost per litre? Try to find out if the cost is same or it differs in different areas, cities, states or countries. We have learnt that fossil fuels are used as motor fuels. What are the other uses of fossil fuels? They are used to make many products like plastics, synthetic fibres, medicines and beauty products. Find out some products made from crude oil. Fuels 3

Amazing Facts The Gevra coal mines in Chhattisgarh is the largest coal mine in India and Asia. It is world’s second largest coal mine. It was opened in 1981. Gevra coal mines Higher Order Thinking Skills (H.O.T.S.) We have learnt that most of the fuels we use are derived from fossil fuels. But, these fuels are in limited quantity. They cannot be produced easily, as their formation takes a long time. They may get over some day. So, they are called non-renewable fuels. Example: fossil fuels (coal, petroleum, oil) and natural gas Some fuels can be produced in a short span of time. The materials required to produce them are continuously available to us. Such fuels are called renewable fuels. For example, biofuels. Biofuels are renewable fuels made from plant and animal materials. Some examples of biofuels are: 1) biogas prepared from animal waste 2) biodiesel prepared from vegetable oils Biofuels are also known as green fuels, as they burn without causing air pollution. 4

Lesson Ways of Communication 15 Let Us Learn About r different ways of communication. u how different ways of communication work. a the benefits and problems of ways of communication. h making my own ways to communicate. Think How do we know what is happening in the neighbouring states and countries? If scientists have discovered a new planet or if it is going to rain today, how do people get to know about it? news channel on TV Remembering Look at the pictures below. Do you know what these are? What are they used for? ____________________ ________________ _________________ __________________ 5

Communication occurs when we pass information from one place to another. To do this, we use newspaper, TV, radio, internet and so on. These are ways to share information. Communication can be between a few people or many people. COMMUNICATION WITH MANY PEOPLE Let us play a game. Make one chit with the name of your favourite cartoon. Pass it on to a friend sitting away from you, without getting up from your place. Did your friend sitting farthest from you get the chit? Communication can be in the written form, audio form and video form. Think of one example of a way of communication in: 1) written form: _________________________________________________________________________ 2) audio form: _________________________________________________________________________ 3) video form: _________________________________________________________________________ COMMUNICATING WITH FEWER PEOPLE Can you tell what is happening in the picture? Sometimes we don’t want to give or pass some information to everyone. We want to give it to only one person or a few people. How do we do that? To communicate to fewer people, we use some other ways. For example, letters, telephone, emails and so on. letters and postcards telephones e-mails 6

Understanding We have seen different ways to communicate. Now let us see how some of them work. WRITTEN FORM – Letters, Postcards and E-mails Let us see how the letters are sent and received. 1) The person who wants to write a letter may use a postcard, an inland letter or a separate paper with an envelope. postcard inland letter envelope with letter 2) People need to write the address of the person to whom the letter is to be sent. They must paste a stamp next to the address. 3) Then, they put the letter in a nearby post box. 4) From the postbox, it is carried to the nearby post office. a letter with stamps on it postbox post office Ways of Communication 7

5) At the post office, the letters are sorted as per the addresses on them. Do you know what happens next? We can also send packets or boxes. Nowadays, many courier services also do the same type of job. Can you name some courier services near your home? These days, we mostly send letters through the internet as e-mails. They reach within seconds. AUDIO FORM – Mobile phones Did you ever make paper boats? How paper boat water waves in a pond do they go from one place to another? Imagine you throw a small rock in a pool. What happens? It causes waves or ripples to go out in all directions. Radio waves are like water waves. Our mobile phones send out signals from a tower radio waves just like the small rock sends out water waves. The radio waves go in all directions until they hit a mobile phone tower. The tower will then send a radio wave to the person you want to talk to. Application Imagine the world without telephones, televisions and computers. We use them every day. They make our lives simpler. But they may sometimes lead to problems. Let us see the benefits and problems of communication in detail. BENEFITS 1) They help us to stay in touch with our family and friends. 2) We can learn new things from the internet using Google, Yahoo!, Wikipedia and so on. We can use them in studies. Use of internet has now become the easiest and fastest way to communicate. Do you know about Facebook and WhatsApp? How do they help us? 8

PROBLEMS We should also use the communication media carefully. 1) Spending lots of time on the mobile phones, computers or TVs may cause health problems. For example, the bright screens of these may harm our eyes. Earphones that we use may be harmful to ears. 2) Spending more time playing video games or using phones, laptops and so on rather than playing outdoors is bad. We do not get enough exercise. This affects our growth and health. at symbol Amazing Facts Do you know the e-mail addresses have a symbol @ as a part of them? This symbol was first used in 1971. This helped the messages to travel from one phone, laptop or computer to another. Do your have an e-mail ID? Write it below. _____________________________________________________________________ If not, then create an e-mail ID for yourself. Write it above. Most often, people use their names in their e-mail IDs. But you may write anything as your e-mail ID. Higher Order Thinking Skills (H.O.T.S.) Did you know, in olden times people used drums and smoke signals to communicate? Then, they learnt to write. Written messages were sent using birds like horse riders, runners or birds like pigeons. People in olden times also communicated through pictographs, cave paintings and so on. drums smoke signalling messenger pigeon Ways of Communication 9

People made their own ways to communicate. Look at the picture given. What are the kids doing? Discuss with your friends. If you have to make your own way of communication, what will it be? 10

Lesson Force and Work 16 Let Us Learn About R force. u types of forces. a work done. h activities where work is not done. Think Rahim was playing cricket. Every time after hitting a six, the ball comes back to the ground. He wondered, why all things fall downwards always? batsman hitting a six things falling downwards Remembering Non-living things around us cannot move on their own from one place to another. How do we make them move? We either push or pull them. push pull 11

Look at the given pictures. To move a trolley, we need to push or pull it. This pull or push to make an object move is force. We also need force to stop a moving object. What do we do to stop a bicycles while riding it? We use the brakes. Through the brakes, we are putting force to stop the wheels from pulling a trolley pushing a trolley rolling. Force is also needed to change the direction of a moving object. When we put more force (push or pull), objects will move faster. When we put less force (push or pull), objects will move slower. Try this: 1) Press against a plastic bottle. Its shape will change. put on force to stop a bicycle We can also change the shape of any object by applying a force. 2) Pull the two edges of the paper in the opposite direction. It will get torn. 3) By pressing a fully blown balloon, it bursts. We can tear or break objects by applying force. What can a force do? 1) A force can make an object move. 2) A force can make a moving object stop. 3) A force can change (increase or decrease) the speed of a moving object. 4) A force can change the direction of a moving object. 5) A force can change the shape of an object. Understanding You have learnt that we apply force to move, stop or change the shape of things. Some forces are acting all the time in nature. Let us learn about them. GRAVITY Sometimes, objects may move or stop without anyone applying any push or pull. For example, rain. Do we pull the raindrops towards the ground? No, they are pulled towards the ground by some other force. In the same way, the ball that we throw up comes back without raindrops ball thrown up anyone pulling it. The force that pulls objects towards the Earth is comes down called gravity. 12