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 \(3\)