Page 93 - Math Skill - 5

Decimal 91

5. Simplify the following.
(a) 98.7 – 93.4 + 102.8 – 56.345 (b) 88.88 – 8.888 + 4.044 – 2.202

6. Fill the missing digits.
(a) 6 . 5 9 (b) 9 . 5 3

+ . 1 – 5 6 . 8

1 5 . 9 8 4 9 . 3

Multiplication of Decimals

Multiplication of decimal by a whole number

To multiply a decimal by a whole number, we follow these steps:

Step 1: Multiply the decimal without the decimal point by the given number.

Step 2: Place the decimal point so as to obtain as many decimal places in the product as
there are in the decimal number.

Let’s learn through examples.

Let’s Attempt

Example 1: Multiply 2.315 by 7.

Solution: First, multiply 2315 by 7
2 3 1 5
× 7 The given decimal number has 3 decimal places.
1 6 2 0 5 Thus, 2.315 × 7 = 16.205.

Example 2: Multiply 3.476 by 135.

Solution: First, multiply 3476 by 135
3 4 7 6
× 1 3 5
1 7 3 8 0
1 0 4 2 8 0 The given decimal has 3 decimal places.
+ 3 4 7 6 0 0
4 6 9 2 6 0 Thus, 3.476 × 135 = 469.260

Multiplication of a decimal by 10, 100 and 1000

Kavita bought 10 notebooks for school. Each notebook costs ` 8.75. What was the total cost of
the notebooks?
To find the total cost, we have to multiply.

` 8 . 7 5 Tens Ones Tenths Hundredths
× 1 0 8 . 7 5 × 10
8 7 . 5 0 8 7 . 5 0