Multiplying by powers of ten


Follow the following shortcut when multiplying by powers of ten

Whole numbers multiplied by powers of 10

When multiplying a whole number by a power of ten, just count how many zero you have and attached that to the whole number

Examples:

1) 56 × 10

There is only one zero, so 56 × 10 = 560

2) 45 × 10,000

There are 4 zeros, so 45 × 10000 = 450000

3) 18 × 10,000,000

There are 7 zeros, so 18 × 10,000,000 = 180,000,000

Decimals multiplied by powers of 10

When multipying a decimal by a positive power of ten (positive exponent), move the decimal point one place to the right for each zero you see after the 1

Examples:

1) 0.56 × 10

There is only one zero, so move the decimal point one place to the right.

0.56 × 10 = 5.6

2) 0.56 × 100

There are 2 zeros, so move the decimal point two places to the right

0.56 × 100 = 56

3) 0.056 × 1000

There are three zeros, so move the decimal point 3 places to the right.

0.056 × 1000 = 56

4) 0.056 × 100,000

0.056 × 100,000 = 0.056 × 1000 × 100 = 56 × 100 = 5600

When multipying a decimal by a negative power of ten (negative exponent), move the decimal point one place to the left for each zero you see before the 1

Note that 0.1 = 10-1, 0.01 = 10-2, 0.001 = 10-3, and so forth....

We call 10-1, 10-2, and 10-3 negative powers of 10 because the exponents are negative

Examples:

1) 56 × 0.1

There is only one zero, so move the decimal point one place to the left.

56 × 0.1 = 5.6

2) 560 × 0.01

There are 2 zeros, so move the decimal point two places to the left

560 × 0.01 = 5.6

2) 560 × 0.001

There are 3 zeros, so move the decimal point two places to the left

560 × 0.001 = 0.560

3) 0.56 × 0.1

There is only one zero, so move the decimal point one place to the left.

0.56 × 0.1 = 0.056

4) 0.56 × 0.01

There are 2 zeros, so move the decimal point two places to the left

0.56 × 0.01 = 0.0056

Any questions about multiplying by powers of ten? Let me know...






Recent Articles

  1. Printable first grade math test

    Mar 24, 17 09:43 AM

    A printable first grade math test that can readily be printed and taken to find out how well you or your kids know very basic concepts of math.

    Read More

New math lessons

Your email is safe with us. We will only use it to inform you about new math lessons.

            Follow me on Pinterest


Page copy protected against web site content infringement by Copyscape






Recent Lessons

  1. Printable first grade math test

    Mar 24, 17 09:43 AM

    A printable first grade math test that can readily be printed and taken to find out how well you or your kids know very basic concepts of math.

    Read More