Negative Numbers
A negative number is any number less than zero, written with a minus sign in front of it (for example -5). Negative numbers describe values below a starting point, like temperatures below freezing, depths below sea level, or a bank balance that has gone overdrawn.
Before you start
Make sure you're comfortable with these topics first:
Method
- Picture a number line: numbers get smaller as you move left of zero and larger as you move right.
- To add a positive number, move right along the number line; to add a negative number, move left instead.
- To subtract a negative number, treat it as adding the positive version instead - two minus signs together become a plus.
- When multiplying or dividing, two numbers with the same sign (both positive or both negative) give a positive answer; two numbers with different signs give a negative answer.
- Work out the size of the answer first, then decide its sign using the rule above.
Worked example
Work out -8 + 3 - (-5).
- Start with -8 + 3. Moving 3 steps to the right of -8 on the number line lands on -5.
- Now deal with - (-5): subtracting a negative is the same as adding, so this becomes -5 + 5.
- -5 + 5 = 0.
- So -8 + 3 - (-5) = 0.
Practice questions
Try each question, then tap to reveal the answer.
Exam-style questions
Written in the style of a GCSE exam paper, with a full mark scheme.
The temperature at midnight is -6 degrees C. By 9am it has risen by 10 degrees, then it falls by 13 degrees by 6pm. What is the temperature at 6pm?
Work out (-5 + 2) x (-3 - 4). Show your working.
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