Q1: Find the following products
(i) 38 x 9
Ans: 38 x 9 = 342
(ii) 80 x 5
Ans: 80 x 5 = 400
(iii) 53 x 8
Ans: 53 x 8 = 424
Q2: Multiply
(i) 4,032 by 198
Ans:
= 4,032 x 198 = 798336
(ii) 3,647 by 245
Ans:
= 3,647 x 245 = 893515
(iii) 501 by 123
Ans:
= 501 x 123 = 61623
Q3: Fill in the blanks
(i) 2,586 x ______ = 2,586
Ans: 2,586 x 1 = 2,586
(Identity Property: The product of any number with 1 is as same as the number itself.)
(ii) 624 x ______ = 38 x 624
Ans: 624 x 38 = 38 x 624
(Commutative property of multiplication is a math rule that says you can multiply numbers in any order, and the result will be the same.)
(iii) 600 x ______ = 0.
Ans: 600 x 0 = 0
(Zero property of multiplication is a fundamental rule in mathematics that states that any number multiplied by zero is equal to zero.)
Q4: Round off the following numbers to the nearest tens
(i) 13,528
Ans: Here’s the general rule for rounding:
- Number >= 5: If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 40.
- Number < 5: If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30.
Therefore, applying these rules, we get:
13,528 = 13,530
(ii) 3,542
Ans: Here’s the general rule for rounding:
- Number >= 5: If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 40.
- Number < 5: If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30.
Therefore, applying these rules, we get:
3,542 = 3,540
(iii) 174
Ans: Here’s the general rule for rounding:
- Number >= 5: If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 40.
- Number < 5: If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30.
Therefore, applying these rules, we get:
174 = 170
Q5: Estimate Products by rounding each number to the nearest Tens
(Find an approximate answer for each multiplication problem by rounding both numbers to the nearest tens place first, then multiplying the rounded numbers.
(i) 52 x 43
Ans: Here’s the general rule for rounding:
- Number >= 5: If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 40.
- Number < 5: If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30.
Therefore, applying these rules, we get:
52 x 43 = 50 x 40 = 2000
(ii) 63 x 52
Ans: Here’s the general rule for rounding:
- Number >= 5: If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 40.
- Number < 5: If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30.
Therefore, applying these rules, we get:
63 x 52 = 60 x 50 = 3000
Q6: Answer the following Questions
(i) Calculate the product of the place values of the two 6s in the number 6,965.
Ans: The place value of 1st 6 in 6,965 is at thousand’s place.
=> First place value of 6 = 6000
The place value of 2nd 6 in 6,965 is at ten’s place.
=> Second place value of 6 = 6000
Product of the place values of 6 in the number 6,965 = 6000 x 60 = 360000
(ii) Find the product of the greatest 2-digit number and the smallest 4-digit number ______.
Ans: Greatest 2-digit no. = 99
Smallest 4-digit no. = 1000
Therefore, the product of the greatest 2-digit number and the smallest 4-digit number = 1000 x 99 = 99000.
(iii) A transistor costs Rs. 1,642. Find the cost of 95 such transistors.
Ans: Cost of one Transistor = Rs 1,642
Total number of transistors = 95
Cost of 95 Transistors = 1642 x 95 = 155,990
(iv) A candle factory produced 814 candles in a day. How many candles will this factory produce in a year?
Ans: A candle factory produces candles in a day = 814
Total number of days in a leap year = 365
Candles this factory will produce in one year = 814 x 365 = 2,97,110
(v) A farmer produced 735 quintals of rice. He sold it at the rate of Rs 1525 per quintal. How much money did he get?
Ans: A farmer produced rice = 735 quintals
Cost per quintal = Rs. 1525
Money he got = 1525 x 735 = Rs. 1,120,875
(vi) The cost of a pack of Ghee is Rs. 308 Find the cost of 97 such packs.
Ans: The cost of 1 pack of Ghee = Rs. 308
Total number of packs = 97
Therefore, Total Cost of 97 packs of Ghee = 308 x 97 = 29,876