Using a number line
A number line can be useful when answering questions involving negative numbers.
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 \(3\).
Now try these questions and remember the number line!
Question
Calculate \(4 - 5\)
Start at \(4\) and go down \(5\).
The answer is \(-1\).
Question
\( - 2 + 5\)
Start at \(-2\) and go up \(5\).
The answer is \(3\).
Question
\(4 - 9\)
Start at \(4\) and go down \(9\).
The answer is \(-5\).
Question
\(3 - 10\)
Start at \(3\) and go down \(10\).
The answer is \(- 7\).
Question
\(- 9 + 12\)
Start at \(-9\) and go up \(12\).
The answer is \(3\)