Page 48 - Math_Genius_V1.0_C7_Flipbook

D:\Surender Prajapati\CBSE_ICSE_Book_New\CBSE\Grade-7\Math_Genius-7\Open_File\02_Chapter\02_Chapter
\ 15-Nov-2024 Surender Prajapati Proof-6 Reader’s Sign _______________________ Date __________

Example 16: Find the products of the following:

(a) 4.256 × 100 (b) 6.66 × 10 (c) 0.094 × 1000
Solution: We have,

(a) On multiplying 4.256 by 100, the decimal point If the number of digits in the
product is less than the total
is shifted by two places to the right. Note: number of decimal places in
\ 4.256 × 100 = 425.6 the number, then put zeros to
the left of the product before
(b) On multiplying 6.66 by 10, the decimal point is placing the decimal point.
shifted by one place to the right.
\ 6.66 × 10 = 66.6

(c) On multiplying 0.094 by 1000, the decimal point is shifted by three places to the
right.

\ 0.094 × 1000 = 94

Practice Time 2E

1. Find the product of the following:
(a) 32.65 × 9 (b) 5.95 × 14 (c) 2.007 × 5 (d) 3.72 × 32
2. Find the product of the following:

(a) 4.64 × 0.62 (b) 1.8 × 5.18 (c) 256.4 × 2.1 (d) 1.8 × 0.007
3. Find the product of the following:
(a) 0.765 × 10 (b) 5.98 × 100 (c) 96.394 × 1000 (d) 0.0082 × 1000

4. If 1 kg wheat costs `36.25, what is the cost of 23.56 kg wheat?
5. A bottle of oil weighs 0.254 kg. What is the weight of 46 such bottles?
6. The cost of 1 m cloth is `58.90. What is the cost of 12.56 m cloth?

7. If 18 × 23 = 414, then find the value of 1.8 × 2.3 without calculation.
8. Fingernails grow 0.1 mm each day. How much do they grow in:

(a) 1 week? (b) in 1 month?

Division of Decimals

Division of a Decimal Number by a Whole Number

Ignore the decimal point and perform division as we do for the whole numbers. Here, the dividend
is a decimal number and the divisor is a whole number.
Then, put the decimal point from the right of the quotient obtained after as many places as in the
given decimal number to the right of the decimal point.

Example 17: Divide the following.
(a) 342.12 by 6 (b) 49.94 by 11

Mathematics-7 46