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 IntegerNegative Integer
Addrightleft
Subtractleftright
Notice:
    • 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

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