Using a number line

A number line can be useful when answering questions involving negative numbers.

Number line spanning minus 8 to plus 8.

When adding a positive number, go up the number line (move to the right).

When subtracting a positive number, go down the number line (move to the left).

Example

6 - 3

Start at 6 and go down 3.

Number line spanning 3 to 6.

Now try these questions and remember the number line!

Question

Calculate 4 - 5

Number line spanning minus 1 to plus 4

Start at 4 and go down 5.

The answer is -1.

Question

 - 2 + 5

Number line spanning minus 2 to plus 3

Start at -2 and go up 5.

The answer is 3.

Question

4 - 9

Number line spanning minus 5 to plus 4

Start at 4 and go down 9.

The answer is -5.

Question

3 - 10

Number line spanning minus 7 to plus 3

Start at 3 and go down 10.

The answer is - 7.

Question

- 9 + 12

Number line spanning minus 9 to plus 3

Start at -9 and go up 12.

The answer is 3