Page 70 & 72
Expenditure for House Construction Material
| Item | Cost per unit (₹) | Number of units | Total amount (₹) |
|---|---|---|---|
| 1. Sand | ₹3000 | 3 | ₹9,000 |
| 2. Cement bricks | ₹16 | 500 | ₹8,000 |
| 3. Iron | ₹80 | 122 kg | ₹9,760 |
| 4. Cement | ₹435 | 50 | ₹21,750 |
| 5. Gravel | ₹4000 | 2 | ₹8,000 |
Page 74 & 76
Do these: Multiplication
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1) Do the following.
a) 245 × 2490 -
b) 2835 × 3
8505
-
c) 3746 × 5
18,730
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d) 4539 × 6
27,234
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2) A factory manufactures 4950 cars in a month. How many cars will the factory produce in a year? (1 year = 12 months)
Cars produced in a month = 4950
Number of months in a year = 12
Total cars produced in a year = 4950 × 12 = 59,400 cars
Page 80
Multiplication with 10, 20, 100, 1000 Table
| 10 × | 20 × | 100 × | 1000 × |
|---|---|---|---|
| 10 × 1 = 10 | 20 × 1 = 20 | 100 × 1 = 100 | 1000 × 1 = 1000 |
| 10 × 2 = 20 | 20 × 2 = 40 | 100 × 2 = 200 | 1000 × 2 = 2000 |
| 10 × 3 = 30 | 20 × 3 = 60 | 100 × 3 = 300 | 1000 × 3 = 3000 |
| 10 × 4 = 40 | 20 × 4 = 80 | 100 × 4 = 400 | 1000 × 4 = 4000 |
| 10 × 5 = 50 | 20 × 5 = 100 | 100 × 5 = 500 | 1000 × 5 = 5000 |
| 10 × 6 = 60 | 20 × 6 = 120 | 100 × 6 = 600 | 1000 × 6 = 6000 |
| 10 × 7 = 70 | 20 × 7 = 140 | 100 × 7 = 700 | 1000 × 7 = 7000 |
| 10 × 8 = 80 | 20 × 8 = 160 | 100 × 8 = 800 | 1000 × 8 = 8000 |
| 10 × 9 = 90 | 20 × 9 = 180 | 100 × 9 = 900 | 1000 × 9 = 9000 |
| 10 × 10 = 100 | 20 × 10 = 200 | 100 × 10 = 1000 | 1000 × 10 = 10000 |
Page 82
Making Word Problems & Do these
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Frame a word problem using: Hema, sarees shop, ₹650 × 5
Word Problem: Hema went to a saree shop and purchased 5 sarees. If the cost of each saree is ₹650, how much total amount did Hema pay?
-
1) a) 3628 × 9
Product: 3628 × 9 = 32,652
Word Problem: A book store sold 3628 notebooks each month for 9 months. What is the total number of notebooks sold? -
1) b) 4256 × 23
Product: 4256 × 23 = 97,888
Word Problem: A garment factory manufactures 4256 shirts in a week. How many shirts will it manufacture in 23 weeks? -
2) Amar sells a cup of tea for ₹6. If 1100 cups of tea was sold on a day, how much amount did he earn?
Price of 1 cup of tea = ₹6
Number of cups sold = 1100
Total amount earned = 1100 × 6 = ₹6,600 -
3) Carpenter Johnson made 9 cots and sold each cot for ₹8,500. How much amount did he earn?
Cost of 1 cot = ₹8,500
Number of cots = 9
Total amount earned = 8500 × 9 = ₹76,500 -
Think & Discuss: Butter packet patterns
a) 2 × 3 = 6 | 3 × 2 = 6
b) 5 × 8 = 40 | 8 × 5 = 40
Page 84
Commutative Property & Multiplication with 1
- c) 6 × 13 = 78 | 13 × 6 = 78
- d) 10 × 5 = 50 | 5 × 10 = 50
- e) 8 × 20 = 160 | 20 × 8 = 160
- f) 12 × 9 = 108 | 9 × 12 = 108
-
Multiplication with 1:
1) 89 × 1 = 89
2) 261 × 1 = 261
3) 4589 × 1 = 4589
Page 86
Multiplication with 0 & Do these
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Multiplication with '0':
1) 56 × 0 = 0
2) 258 × 0 = 0
3) 0 × 953 = 0 -
Do these:
1. Find the products: 46 × 23 and 23 × 46.46 × 23 = 1058
23 × 46 = 1058
Both products are equal. -
2. Do the following:
a) 23 × 1 = 23
b) 342 × 1 = 342
c) 999 × 1 = 999
d) 53 × 0 = 0
e) 259 × 0 = 0
f) 5817 × 0 = 0
Page 88
Do these: Estimate the Products & Division Intro
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Estimate the products of these multiplications:
1) 59 × 19 ≈ 60 × 20 = 1200 (Exact = 1121)
2) 99 × 56 ≈ 100 × 60 = 6000 (Exact = 5544)
3) 189 × 33 ≈ 200 × 30 = 6000 (Exact = 6237) -
Division Intro Questions:
1. How many books were donated to the library?9984 books. -
2. How many almirahs were donated by Mr. Raju?
8 almirahs.
-
3. Which operation is required to arrange the books equally in almirahs?
Division (9984 ÷ 8 = 1248 books per almirah).
Page 94
Do these: Divisions & Unitary Method
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1) a) 9786 ÷ 6
Dividend = 9786, Divisor = 6, Quotient = 1631, Remainder = 0
Verification: (6 × 1631) + 0 = 9786 -
1) b) 5682 ÷ 9
Dividend = 5682, Divisor = 9, Quotient = 631, Remainder = 3
Verification: (9 × 631) + 3 = 5679 + 3 = 5682 -
2) Raju bought 120 blankets with ₹6000 to distribute to orphans. What is the cost of each blanket?
Total cost = ₹6000
Number of blankets = 120
Cost of each blanket = 6000 ÷ 120 = ₹50 -
3) Divisions by 10, 100, 1000, 10000:
a) 53427 ÷ 10 → Quotient = 5342, Remainder = 7
b) 53427 ÷ 100 → Quotient = 534, Remainder = 27
c) 53427 ÷ 1000 → Quotient = 53, Remainder = 427
d) 53427 ÷ 10000 → Quotient = 5, Remainder = 3427 -
Unitary Method - Do these:
1. If 8 pots cost ₹800, what would be the cost of 5 pots?Cost of 1 pot = 800 ÷ 8 = ₹100
Cost of 5 pots = 100 × 5 = ₹500 -
2. If 5 kg tomatoes cost ₹125, what would be the cost of 2 kg tomatoes?
Cost of 1 kg tomato = 125 ÷ 5 = ₹25
Cost of 2 kg tomatoes = 25 × 2 = ₹50 -
3. A publisher printed 3,875 books in the month of July. If publisher makes the same number of books in every month, how many books can be printed in a leap year? (1 year = 12 months)
Books per month = 3875
Total books in 12 months = 3875 × 12 = 46,500 books
Page 96 & 98
Estimation & Fact Families
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Labour Estimation Problem: 4 Labourers agreed to work for ₹4250. Whose estimation is correct? (Bhima: ₹1500, Ahmed: ₹1000, Saradha: ₹700, Laxmi: ₹800)
Answer: Ahmed estimated correctly (4000 ÷ 4 = ₹1000).
-
Do these: 1. Estimate the result.
a) 309 ÷ 11 ≈ 300 ÷ 10 = 30 (Exact = 28.09)
b) 497 ÷ 23 ≈ 500 ÷ 25 = 20 (Exact = 21.6)
c) 891 ÷ 32 ≈ 900 ÷ 30 = 30 (Exact = 27.84) -
2. Johnny bought 5 packets of buns each containing 20. If he distributed equally to 48 patients, how many buns will each patient get approximately?
Total buns = 5 × 20 = 100
Approximate distribution = 100 ÷ 50 = 2 buns per patient.
Relation between Multiplication and Division Table
| Multiplication | Division fact-1 | Division fact-2 |
|---|---|---|
| 10 × 2 = 20 | 20 ÷ 2 = 10 | 20 ÷ 10 = 2 |
| 23 × 4 = 92 | 92 ÷ 4 = 23 | 92 ÷ 23 = 4 |
| 52 × 12 = 624 | 624 ÷ 12 = 52 | 624 ÷ 52 = 12 |
| 500 × 4 = 2000 | 2000 ÷ 4 = 500 | 2000 ÷ 500 = 4 |
| 36 × 18 = 648 | 648 ÷ 18 = 36 | 648 ÷ 36 = 18 |
| 527 × 15 = 7905 | 7905 ÷ 15 = 527 | 7905 ÷ 527 = 15 |
Page 100
Multiplication forms for Divisions Table
| Division form | Multiplication form |
|---|---|
| 54 ÷ 6 = 9 | 9 × 6 = 54 |
| 168 ÷ 12 = 14 | 14 × 12 = 168 |
| 792 ÷ 22 = 36 | 36 × 22 = 792 |
| 200 ÷ 5 = 40 | 40 × 5 = 200 |
| 1265 ÷ 23 = 55 | 55 × 23 = 1265 |
| 2262 ÷ 39 = 58 | 58 × 39 = 2262 |
EXERCISE
Problems 1 to 3
-
1. The cost of a bicycle is ₹4,950. The cost of a motor cycle is 13 times the bicycle's cost. What is the cost of the motor cycle?
Cost of bicycle = ₹4,950
Cost of motorcycle = 4950 × 13 = ₹64,350 -
2. A carton can hold 36 mangoes. How many such cartons are required if there are 4,320 mangoes in all?
Total mangoes = 4320
Capacity of 1 carton = 36
Cartons required = 4320 ÷ 36 = 120 cartons -
3. The owner of a cell phone shop bought 8 cell phones at the same price and he gave ₹9,800 to wholesaler. The wholesaler returned him ₹200. What is the cost of each cell phone?
Amount paid = ₹9800 - ₹200 = ₹9600
Number of cell phones = 8
Cost of each cell phone = 9600 ÷ 8 = ₹1,200
Page 102
Exercise Problems 4 to 9
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4. A fisherman wants to sell 8 kg of fish for ₹1,600. But Ramu wants to buy 5 kg only. Find the cost of 5 kg fish?
Cost of 1 kg fish = 1600 ÷ 8 = ₹200
Cost of 5 kg fish = 200 × 5 = ₹1,000 -
5. Harsha painted pictures and sold them in an art gallery. He charged ₹2,567 for a big painting and ₹465 for a small painting. He sold 6 large paintings and 3 small paintings. How much amount did he earn?
Earnings from 6 large paintings = 2567 × 6 = ₹15,402
Earnings from 3 small paintings = 465 × 3 = ₹1,395
Total earnings = 15402 + 1395 = ₹16,797 -
6. The cost price of 3kg apples is ₹360 then find the cost of apples for 2 kg.
Cost of 1 kg apples = 360 ÷ 3 = ₹120
Cost of 2 kg apples = 120 × 2 = ₹240 -
7. Swetha multiplied the number of eggs in her basket by 312. The answer was a number between 4000 and 4300. What could be the number of eggs in her basket?
Answer: D) 13 (312 × 13 = 4056)
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8. A shop keeper had 297 story books. He wanted to pack them equally into 8 boxes. How many story books would be left unpacked?
Answer: A) 1 (297 ÷ 8 = 37 with remainder 1)
-
9. Quick 5-Minute Problems:
- 300 × 5 = 1500
- Spelling mistake: 'Divition' (Correct: Division)
- If 8 books cost ₹800, 5 books cost: ₹500
- 200 ÷ 5 = 40 → Multiplication form: 40 × 5 = 200
- 390 ÷ 13 = 30
- 426 × 24 = 24 × 426
- Estimate 13 × 21 ≈ 10 × 20 = 200 (Exact = 273)
- 3650 × 0 = 0
- Dividend = (Divisor × Quotient) + Remainder
Page 104
Improve Your Learning
- 1. In 5436 ÷ 7, Quotient = 776, Remainder = 4
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2. 345 books were bought for the school library. These books have to be packed into boxes that hold 15 books each. Which of the following could be used to find the number of boxes needed?
Answer: d) Divide 345 by 15
-
3. A school group is heading to the zoo on six buses. The first five buses, each accommodating 40 students, are full. The last bus has 5 empty seats. In total, how many students are going to the zoo?
Students in first 5 buses = 5 × 40 = 200
Students in 6th bus = 40 - 5 = 35
Total students = 200 + 35 = 235 students -
4. A division problem solved correctly: 666 ÷ 6 = 106. (Empty box in middle is 0).
Digit in empty box = 0
-
5. Shop 'A' sells a pack of 5 pens for ₹100. Shop 'B' sells a pack of 8 pens for ₹152. Is the cost of a pen lower in price in shop 'A' compared to shop 'B'?
Cost of 1 pen in Shop A = 100 ÷ 5 = ₹20
Cost of 1 pen in Shop B = 152 ÷ 8 = ₹19
Answer: No. A pen in Shop B (₹19) is cheaper than Shop A (₹20). -
6. Cost of 1 meal is ₹110. If you have ₹1000, how many meals can you arrange? To arrange 1 more meal, how much money do you need?
1000 ÷ 110 = 9 meals (Cost = ₹990), Remaining money = ₹10.
To arrange 10th meal (₹110), money needed = 110 - 10 = ₹100. -
7. A pension holder gets a pension of ₹9950 per month. How much pension will he get in one year? (1 year = 12 months)
Pension in 1 year = 9950 × 12 = ₹1,19,400
-
8. Sara wants to buy a certain kind of toy. Each toy cost ₹1,000. If she has ₹50,000, how many toys can she buy?
Number of toys = 50000 ÷ 1000 = 50 toys
-
9. A shopkeeper had 4297 storybooks. He wanted to pack them equally into 18 boxes. How many storybooks would be left unpacked?
4297 ÷ 18 = 238 boxes with remainder 13.
Storybooks left unpacked = 13 storybooks. -
10. 28 laddoos weigh 1 kg. How many laddoos weigh 12 kgs? If 16 laddoos can be packed in one box, how many boxes are needed to pack all these laddoos?
Total laddoos in 12 kg = 28 × 12 = 336 laddoos
Boxes needed = 336 ÷ 16 = 21 boxes
