# Multiplying and dividing by 10 and 100

• To multiply a number by 10, move the digits one place to the left, adding a zero if necessary.

58 x 10 = 580

58 multiplied by 10 = 580

• To multiply a number by 100, move the digits two places to the left, adding zeros if necessary.

58 x 100 = 5800

58 multiplied by 100 = 5800

• To multiply a decimal number by 10, move the digits one place to the left, losing the decimal point and adding a zero if necessary.

7.3 x 10 = 73

• To divide a number by 10, move the digits one place to the right, taking away a zero if necessary.

7210 ÷ 10 = 721

• To divide a number by 100, move the digits two place to the right, taking away a zero if necessary.

15,000 ÷ 100 = 150

• To divide a decimal number by 10, move the digits one place to the right, adding a zero if necessary.

4.3 ÷ 10 = 0.43

• To divide a decimal number by 100, move the digits two places to the right, adding zeros if necessary.

4.3 ÷ 10 = 0.043

• To multiply or divide by numbers such as 20 or 300, multiply or divide by the 2 or 3 first and then by the 10 or 100.

To do 24 ÷ 20, you could divide 24 by 2 and then divide that answer by 10.

24 ÷ 2 = 12

12 ÷ 10 = 1.2

To do 22 x 300, you could multiply 22 by 3 and then multiply that answer by 100.

22 x 3 = 66

66 x 100 = 6600

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