Page 69 - Start Up Mathematics_3

Multiplication by 100

To multiply a number by 100, write the number followed by two zeros at the end.

For example, 8 × 100 = 800 96 × 100 = 9600 342 × 100 = 34200

To multiply a number by 200, 300, 400, 500 and so on, write two zeros at the end,
multiply the number by the remaining digit(s) and write their product before the two
zeros.

For example, 6 × 3 00 = 1800 19 × 4 00 = 7600 243 × 6 00 = 145800

3 2 1
1 9 2 4 3
× 4 × 6
7 6 1 4 5 8

Multiplication by 1000

To multiply a number by 1000, write the number followed by three zeros at the end.

For example, 4 × 1000 = 4000 52 × 1000 = 52000 713 × 1000 = 713000

To multiply a number by 2000, 3000, 4000, 5000 and so on, write three zeros at the
end, multiply the number by the remaining digit(s) and write their product before
the three zeros.

For example, 6 × 2 000 = 12000 47 × 5 000 = 235000 361 × 9 000 = 3249000

3 5
Mental Maths 4 7 3 6 1

× 5 × 9
20 × 10 = ?
40 × 200 = ? 2 3 5 3 2 4 9

Multiplication of Two 2-Digit Numbers

Without carrying over (without regrouping)

Example 4: Find the product of 32 and 12.

T O

Solution: 3 2 ← Multiplicand

× 1 2 ← Multiplier

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