Math Skill: Integer Subtraction
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View Lesson | View Sample Problems | Do Worksheet
Instructional videos are displayed with permission from Khan Academy.
Integer Subtraction
This topic will be easier if you know how to add integers.To review the Integer Addition topic, see here.
This topic covers the subtraction of positive and negative numbers.
Subtraction is the opposite of addition. Their movement on the number line is also the opposite.
| Movement on the Number Line | ||
|---|---|---|
| Positive Integer | Negative Integer | |
| Add | right | left |
| Subtract | left | right |
• Subtracting negative integers = Adding positive integers
• Adding negative integers = Subtracting positive integers
Positive - Positive
3 - 5
a. Start at +3 on the number line b. From +3, move 5 to the left to subtract +5 You end up at -2
3 - 5 = -2
Notice that 3 - 5 = 3 + -5
Positive - Negative
1 - -2
a. Start at +1 on the number line b. From +1, move 2 to the right to subtract -2 You end up at +3
1 - -2 = 3
Notice that 1 - -2 = 1 + 2
Negative - Positive
-1 - 3
a. Start at -1 on the number line b. From -1, move 3 to the left to subtract +3 You end up at -4
-1 - 3 = -4
Notice that -1 - 3 = -1 + -3
Negative - Negative
-3 - -4
a. Start at -3 on the number line b. From -3, move 4 to the right to subtract -4 You end up at +1
-3 - -4 = 1
Notice that -3 - -4 = -3 + 4




