Rules for Adding and Subtracting Decimals

When adding or subtracting with decimals, you -

• Move decimals out

• Shift decimals 3 places over

• Line up the decimals

• Ignore decimals

The place value right after the decimal is called the __________.

• tens

• tenths

• thousands

• hundrenths

When adding decimals with the same sign you.....

• subtract and take the sign of the larger number

• add the opposite

• add and keep the sign

• subtract and keep the sign

Rewrite the problem as addition.

-5.66 - (-4.1)

• 5.66 + (-4.1)

• -5.66 + 4.1

• -5.66 + (-4.1)

• -5.66 - 4.1

-23.4 - 3.4= 

• -20

• 26.8

• -26.8

• 20

-40 + 15.05= 

• 55.05

• 24.95

• -24.95

• 14.65

What is the value of 18 - 23.2 ?

• -5.2

• -5.8 

• 5.2

• 5.8

What is the FIRST step when adding and subtracting decimals?

• Line up the numbers

• Line up the decimal points

• Add or subtract like normal

• Add in placeholders

What is the rule for adding and subtracting positive decimals?

• Line up the decimals and then add/subtract normally

• You do not have to worry about placement of the decimal

• Forget the decimal and move it that many spaces at the end

• Drop it down and move it to the right once

When adding or subtracting decimals, you must line up your decimal points.

• TRUE

• FALSE