Page 104 & 106
4.0 Introduction & 4.1 Multiplication of 3-digit number by 1-digit number
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How much should we pay for our 3 tickets? (Entry fee: ₹60 per person)
3 × 60 = ₹180
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How much did Amar and his friends (12 members) pay for 12 tickets?
12 × 60 = ₹720
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Ramya, Yaswanth and their uncle bought 3 teddy bears at a price of ₹145 each. How much money did the shopkeeper get?
145 × 3 = ₹435
Page 110
Do these
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1. Find the products using expanded form method and observe the answers.
a) 164 × 2(100 × 2) + (60 × 2) + (4 × 2) = 200 + 120 + 8 = 328 -
b) 246 × 3
(200 × 3) + (40 × 3) + (6 × 3) = 600 + 120 + 18 = 738
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c) 209 × 4
(200 × 4) + (0 × 4) + (9 × 4) = 800 + 0 + 36 = 836
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2. Verify the following and correct them wherever necessary.
a) 264 × 2 = 4128Incorrect. Correct Product: 264 × 2 = 528 -
b) 342 × 3 = 1026
Correct: 342 × 3 = 1026
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c) 213 × 4 = 8412
Incorrect. Correct Product: 213 × 4 = 852
Try these
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1. In Inapuru school, there are 156 pupils. The teacher asked them to plant 4 saplings for each student in the village. How many saplings did they plant?
Number of pupils = 156
Saplings per student = 4
Total saplings planted = 156 × 4 = 624 saplings -
2. If a box contains 164 mangoes, how many mangoes will be there in 5 such boxes?
Mangoes in one box = 164
Number of boxes = 5
Total mangoes = 164 × 5 = 820 mangoes -
3. Ramayya went to agriculture work for 2 days. If his wage was ₹425 per day, what was the total wage for 2 days?
Wage per day = ₹425
Number of days = 2
Total wage = 425 × 2 = ₹850 -
4. Giant wheel ticket cost for 12 members at ₹100 per person:
12 × 100 = ₹1200
Page 112
Do these: Multiplication with 100's
- 1) 4 × 100 = 400 | 100 × 4 = 400
- 2) 6 × 100 = 600 | 100 × 6 = 600
- 3) 12 × 100 = 1200 | 100 × 12 = 1200
- 4) 14 × 100 = 1400 | 100 × 14 = 1400
Page 114
Do these: Multiplication using straws method
- a) 114 × 3 = 342
- b) 314 × 4 = 1256
- c) 213 × 5 = 1065
- d) 134 × 6 = 804
- e) 243 × 5 = 1215
- f) 126 × 7 = 882
Page 118
Do these: 3-digit by 2-digit multiplication
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1. Do the following multiplications
a) 342 × 15342 × 15 = 5130 -
b) 423 × 21
423 × 21 = 8883
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c) 233 × 26
233 × 26 = 6058
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2. How many trees are there in the garden, if there are 124 rows and each row contains 65 trees?
Number of rows = 124
Trees in each row = 65
Total trees = 124 × 65 = 8060 trees -
3. The owner of a dairy farm sold 496 milk packets in 15 days. If each packet was sold at ₹25, how much money did he earn?
Total milk packets = 496
Price per packet = ₹25
Total money earned = 496 × 25 = ₹12,400
Page 120
4.3 Fun with multiplication
- b) 13 × 93 = 1209 | 31 × 39 = 1209
- c) 26 × 93 = 2418 | 62 × 39 = 2418
- d) 42 × 36 = 1512 | 24 × 63 = 1512
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Pattern 1: Multiply and add
37 × 3 = 111
37 × 6 = 222
37 × 9 = 333
37 × 12 = 444
37 × 15 = 555 -
Pattern 2:
1 × 9 + 2 = 11
12 × 9 + 3 = 111
123 × 9 + 4 = 1111
1234 × 9 + 5 = 11111
Page 122
EXERCISE-1
Questions & Problems
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1. Multiply
a) 348 × 3712,876 -
b) 456 × 48
21,888
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2. The cost of a chair is ₹375. What is the cost of 18 such chairs?
Cost of 1 chair = ₹375
Cost of 18 chairs = 375 × 18 = ₹6,750 -
3. Raju delivers 157 newspapers each morning. How many newspapers does he deliver in 31 days?
Newspapers per day = 157
Number of days = 31
Total newspapers = 157 × 31 = 4,867 newspapers -
4. 42 children in a class planned a picnic. If each child contributes ₹168, how much money was collected?
Number of children = 42
Contribution per child = ₹168
Total money collected = 168 × 42 = ₹7,056 -
5. Arjun buys 65 crates of mangoes at ₹285 per crate. How much money does Arjun pay?
Number of crates = 65
Price per crate = ₹285
Total amount paid = 285 × 65 = ₹18,525 -
6. A hostel needs 145kg of rice everyday. How many kilograms of rice are required for the month of August? (August = 31 days)
Answer: d) 4495 kg (145 × 31 = 4495)
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7. How many minutes a day? (1 hour = 60 minutes, 1 day = 24 hours)
Answer: b) 1440 minutes (24 × 60 = 1440)
Project work
| S.No | Commodity | Price per 1kg (in ₹) | Quantity (in kgs) | Total cost (in ₹) |
|---|---|---|---|---|
| 1 | Rice | ₹50 | 120 kg | ₹6000 |
| 2 | Black-gram | ₹120 | 45 kg | ₹5400 |
| 3 | Green-gram | ₹110 | 35 kg | ₹3850 |
| 4 | Red-gram | ₹140 | 43 kg | ₹6020 |
| 5 | Bengal-gram | ₹80 | 40 kg | ₹3200 |
| 6 | Sugar | ₹42 | 26 kg | ₹1092 |
| Total Amount Required | ₹25,562 | |||
Page 124 & 126
Introduction of Multiples - Animal Jumps
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1. The frog jumps 3 steps at a time (Multiples of 3: 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30...)
a) At which number frog catch the bee?Answer: 36 (or the marked flower number) -
b) Which number will the frog reach on it's 10th jump?
10 × 3 = 30
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c) Write the multiples of 3?
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36...
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2. The squirrel jumps 4 steps at a time (Multiples of 4: 0, 4, 8, 12, 16, 20, 24, 28, 32...)
a) At which number the squirrel get the nut?Answer: 36 (or the position of nut) -
b) Which number the squirrel reach after 12th jump?
12 × 4 = 48
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c) Write the multiples of 4?
4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48...
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3. The rabbit jumps 6 steps at a time:
a) At which number is the carrot placed?Answer: 48 (or multiple of 6) -
b) Write the multiples of 6?
6, 12, 18, 24, 30, 36, 42, 48, 54, 60...
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4. The Kangaroo jumps 8 steps at a time:
a) These numbers are multiples of 8
b) Write the multiples of 8:8, 16, 24, 32, 40, 48, 56, 64, 72, 80... -
Think and Discuss: Cat is on 6 (jumps 3 steps), Rat is on 12 (jumps 2 steps). Will the cat catch the rat? At which number?
Cat's positions: 6, 9, 12, 15, 18, 21, 24, 27, 30
Rat's positions: 12, 14, 16, 18, 20, 22, 24, 26, 28
After 6 jumps: Cat is on 6 + (6×3) = 24, Rat is on 12 + (6×2) = 24.
Yes, the cat will catch the rat at number 24.
Page 128 & 130
Multiples from Chart
- Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30...
- Multiples of 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65...
- Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
EXERCISE-2
Exercises on Multiples
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1. Find the first 5 multiples of each of the following:
a) 3 : 3, 6, 9, 12, 15
b) 7 : 7, 14, 21, 28, 35
c) 8 : 8, 16, 24, 32, 40 -
2. Write the multiples of 8 below 100:
8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96
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3. True (T) or False (F):
a) 12 is a multiple of 3 ( T )
b) 57 is a multiple of 8 ( F )
c) 30 is a multiple of 5 ( T )
d) 47 is a multiple of 6 ( F )
e) 52 is a multiple of 4 ( T ) -
4. Circle the multiples of 3 in: 2, 5, 6, 9, 10, 14, 20, 21, 27, 32, 37, 36, 48.
Multiples of 3: 6, 9, 21, 27, 36, 48
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5. Numbers which are NOT multiples of 4 in: 2, 4, 8, 11, 20, 21, 27, 28, 30, 32, 37, 40, 45, 57.
Not multiples of 4: 2, 11, 21, 27, 30, 37, 45, 57
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6. Circle the multiples of 5 in: 2, 4, 14, 20, 21, 27, 35, 55, 25, 68, 65, 22, 39.
Multiples of 5: 20, 35, 55, 25, 65
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7. Numbers which are NOT multiples of 8 in: 20, 24, 45, 32, 35, 26, 90, 8, 7, 10.
Not multiples of 8: 20, 45, 35, 26, 90, 7, 10
Page 132
Improve Your Learning
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1. Ramaiah purchased 9 chairs from a furniture store, each costing ₹303. Which of the below expressions shows the total cost of the chairs?
Answer: c) (9 × 300) + (9 × 0) + (9 × 3)
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2. In a school, eggs are supplied in trays every week. Each tray contains 30 eggs.
a) In the first week of July, a total of 6 trays were supplied. How many eggs were supplied?6 × 30 = 180 eggs -
b) If 7 trays of eggs were distributed in the second week, how many eggs were distributed in that week?
7 × 30 = 210 eggs
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c) Vasu said that adding 30 to the number of eggs distributed in the first week would give the number of eggs distributed in the second week. Is it correct?
Yes, it is correct (180 + 30 = 210 eggs).
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3. A library has 5 rows of desks. Each row has 6 desks. If 2 students sit at each desk, how many students can study in the library at the same time?
Total desks = 5 × 6 = 30 desks
Students per desk = 2
Total students = 30 × 2 = 60 students -
4. Each box contains 6 crayons.
a) What is the total number of crayons in all the 5 boxes?5 × 6 = 30 crayons -
b) What is the total number of crayons if one box is removed?
4 × 6 = 24 crayons
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5. A student bought 8 identical packets of pens. After giving 5 packets to his classmates, he had 12 pens left. How many pens did he have in total at the beginning?
Packets left = 8 - 5 = 3 packets
Pens in 3 packets = 12 pens
Pens in 1 packet = 12 ÷ 3 = 4 pens
Total pens at the beginning = 8 × 4 = 32 pens -
6. Riddle: "I am a multiple of 7. I am greater than 20 but less than 30. If you add my digits together, the sum is 10. Who am I?"
Multiples of 7 between 20 and 30 are 21 and 28.
For 28: 2 + 8 = 10
Answer: 28
