in GED Practice Tests

How to subtract signed numbers

By Mr. Feliz

Rule:

Change the sign of the number you are subtracting and then follow the rules for addition of signed numbers.

10 - (-5) =

We change -5 to +5 and the problem from subtraction to addition.

10 - (-5) becomes 10 + (+5) = 15

-14 - (-15) =

We change -15 to +15 and the problem from subtraction to addition.

-14 - (-15) becomes -14 + (+15) = 1

-12 - (+3) =

We change +3 to -3 and the problem from subtraction to addition.

-12 - (+3) becomes -12 - 3 = -15

(1) 50 - (-60) =

(2) -25 - (-12) =

(3) -100 - (+56) =

(4) 60 - (+70) =

(5) 500 - (- 70) =

By Mr. Feliz

Rule:

Change the sign of the number you are subtracting and then follow the rules for addition of signed numbers.

**Sample A:**10 - (-5) =

We change -5 to +5 and the problem from subtraction to addition.

10 - (-5) becomes 10 + (+5) = 15

**Sample B:**-14 - (-15) =

We change -15 to +15 and the problem from subtraction to addition.

-14 - (-15) becomes -14 + (+15) = 1

**Sample C:**-12 - (+3) =

We change +3 to -3 and the problem from subtraction to addition.

-12 - (+3) becomes -12 - 3 = -15

**Practice Questions:**

(1) 50 - (-60) =

(2) -25 - (-12) =

(3) -100 - (+56) =

(4) 60 - (+70) =

(5) 500 - (- 70) =