Adding and Subtraction with Decimals

When adding or subtracting with decimals, you...

• Line up the digits.

• Line up the decimals.

• Move the decimal to make a whole number.

• Raise the decimal "to the roof."

The inverse operation of addition is...

• Addition

• Subtraction

• Multiplication

• Division

When the divisor has a decimal, AND the dividend has a decimal, you

• Line up the decimals.

• Line up the digits.

• Move the decimal to make the divisor a whole number and move the decimal in the dividend the same number of times.

• Raise the decimal "to the roof."

When the dividend has a decimal, but the divisor does NOT, you...

• Line up the digits.

• Line up the decimals.

• Move the decimal in the dividend to make a whole number.

• Raise the decimal "to the roof."

• 195.02

• 33.66

• 72.54

• 33.6

• 8.49

• 2.99

• 6.79

• 3.29

• 4.60

• 40.08

• 29.48

• 9.92

• 0.45

• 0.55

Subtract 6.5 from 10.2.

• 3.2

• 3.7

• 4.2

• 3.8

Answer explanation

To subtract 6.5 from 10.2, write the numbers vertically lining up the decimal points then subtract. When you bring down the decimal point, you get 3.7. Therefore, the correct answer is 3.7.

• 11.01

• 8.99