Positive & Negative Numbers

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

This video explains more about how this works

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

This video explains how to multiply negative numbers

This video shows you how to divide negative numbers

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