Negative Numbers


Negative numbers will crop up all the time in your maths exam.  They will not normally be stand alone questions but instead form part of another topic.  You must study the rules for + - x carefully when working with negative numbers.

Example Question

Calculate:

a) 6 + -14
b) -4 -
-6
c) 
-6 x 5
d)
-40  -8


Solution
a)
When adding a negative number to another number the sum becomes a subtraction.
So:
6 + -14 = 6 - 14 = -8

b)
When subtracting a negative number from another number the sum becomes an addition.
So:
-4 --6 = -4 + 6 = 2

c)
When multiplying negatives just do the sum as you normally would then make your answer negative.  However, if both numbers are negative then your answer becomes positive.
So:
 -6 x 5 = -30

d)
When dividing negatives the rule is the same as when multiplying negatives.  Remember, if both numbers are negative then your answer becomes positive.  In this case both numbers are negative.
So:
-40  -8 = 5


Test Yourself!
Calculate -6 x 4 
Write down the value of -16 divided by -2.
Work out (-3)2 + -5
In London the temperature was 2oC.  The temperature in Moscow was 11oC lower.
What was the temperature in Moscow?
Given a = 2 and b = -3, find the value of b2 - ab.
Find the value of x2 - 2x + 4 when x = -1.


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