To work out -3 + 5 we start at -3 on a number line and count forward 5 to get to 2.
So -3 + 5 = 2
To work out -4 - 5 we start at -4 on a number line and count back 5 to get to -9
So -4 - 5 = -9
Let's practise some more adding and subtracting negative numbers in the following questions.