Academic Skills Advice
Summary
Negative Numbers
A negative number is one which is less than 0. Remember the minus (negative) sign is
always in front of the number it is connected to.
You need to know how to perform all 4 rules (+, -, x and ÷) with negative numbers.
Adding and Subtracting
In general if the negative number is the biggest you will end up with a negative answer and
vice versa. Remember that subtract (take away or minus) is the difference between the
2 numbers.
Examples:
𝟖– 𝟓 = 𝟑
𝟓 – 𝟖 = −𝟑
(you are taking away more than you started with)
−𝟖 + 𝟓 = −𝟑
−𝟔 – 𝟕 = −𝟏𝟑 (take away 6 and take away another 7)
etc
If you are presented with a calculation such as:
𝟗 − (−𝟑) (9 take away minus (or negative) 3).
The difference between 9 and (−3) is:
To get from 9 to 0 = 9
To get from 0 to -3 = 3
The total distance between 9 and (−3) is 12.
An easy thing to remember is that 2 minus signs together can be replaced with a +.
e.g.
9 − (−3) = 9 + 3 = 12
Multiplying and Dividing
Here we need to remember our rule about 2 minus signs together being replaced with a +.
The following is an important summary when using x and ÷ with negative numbers:
When multiplying or dividing:
2 signs the same gives +
2 different signs gives –
© H Jackson 2010 / ACADEMIC SKILLS
+ and +
- and + and - and +
=+
=+
==1