Negative numbers and counting through zero
Maths · Key Stage 2 · The School
Numbers below zero
Every number line you have used so far starts at zero and goes up. But numbers carry on below zero too. Minus one, minus two, minus three — each one sits to the left of zero. They are called negative numbers, and they measure how far below zero something is. The further left a number sits, the smaller it actually is, even though it might not look that way at first.
Where you meet them
A cold winter morning might be minus 3 degrees. A lift might go down to floor minus 2, below the ground floor. Money owed is sometimes shown as a negative amount. Negative numbers are not just a maths trick — they describe real things that sit below a starting point. Once you start looking, you notice negative numbers appearing in weather reports, in lifts, and on bank statements.
Counting through zero
Count from 3 down to minus 3. It goes 3, 2, 1, 0, minus 1, minus 2, minus 3. Zero is not skipped, and it is not negative or positive itself — it sits exactly in the middle. The trickiest part is remembering that after 1 comes 0, and only then comes minus 1.
Working out a temperature change
The temperature is 4 degrees. Overnight it drops by 7 degrees. Count down from 4: 3, 2, 1, 0, minus 1, minus 2, minus 3. Seven steps down from 4 lands on minus 3. So the new temperature is minus 3 degrees. Counting the steps one at a time, right through zero, avoids the easy mistake of stopping too early.