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exploriNg MulTipliCATioN

Multiplying by expanding the Bigger Number

example 1. Multiply: 67 × 5 example 2. Multiply: 143 × 3
Solution. Solution.

Step 1. 67 × 5 = ? 67 Step 1. 143 × 3 = ? 143

60 + 7 100 + 40 + 3
Step 2. 60 × 5 = 300 Step 2. 100 × 3 = 300

7 × 5 = + 35 40 × 3 = 120
335 3 × 3 = + 9

429

So, 67 × 5 = 335. So, 143 × 3 = 429.

Multiplying by 1
observe the following:

a. 7 × 1 = 7 b. 53 × 1 = 53 c. 124 × 1 = 124
When a number is multiplied by 1, the product is the number itself.

Multiplying by Zero
observe the following:

a. 5 × 0 = 0 b. 17 × 0 = 0 c. 124 × 0 = 0
When a number is multiplied by zero, the product is always zero.

Multiplying by 10
Look at the following multiplications.

a. 3 × 10 = 30 b. 12 × 10 = 120 c. 324 × 10 = 3240
To multiply a number by 10, write a ‘0’ to the right of the number.

Multiplying by Tens other than 10

Observe the following multiplications.
a. 12 × 20 = 240 b. 36 × 30 = 1080 c. 26 × 60 = 1560

To multiply a number by 20, 30, 40, ..., 90, first multiply the numbers without zero.
Then add a zero (0) to the right of the product obtained.
Multiplying by 100

Let us see how to multiply a number by 100.

a. 1 × 100 = 100 b. 5 × 100 = 500 c. 17 × 100 = 1700
To multiply a number by 100, write two zeros (00) to the right of the number.

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Multiplication