Numbers can either be positive or negative. Often brackets are put around
negative numbers to make them easier to read, e.g. (2). If a number is
positive, the + is usually missed out before the number. So 3 is really (+3).
Adding and multiplying combinations of positive and negative numbers can cause
confusion and so care must be taken.
Addition and Subtraction
Two 'pluses' make a plus, two 'minuses' make a plus. A plus and a minus make
a minus.
Example
3 + (2) A plus and a minus make a minus, so this is the
same as 3  2 = 1
Example
(2) + (5) = 7 This is the same as (2)  5 = 7
Multiplication and Division
If two positive numbers are multiplied together or divided, the answer is
positive. If two negative numbers are multiplied together or divided, the
answer is positive. If a positive and a negative number are multiplied or
divided, the answer is negative.
Examples
(2) ÷ (4) = ½ (8) ÷ (2) = (4) 2 × (3) =
(6) (2) × (2) = 4
Copyright © Matthew Pinkney 2003
