Starting at 0 we can count up in units like this:

0 1 2 3 4 5 6 7 ...

But what happens before zero?

We have the negative numbers, like this:

... -7 -6 -5 -4 -3 -2 -1 0

That was counting **UP**.

Now let's count **BACKWARDS **from **7**.

7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 ...

**Example**

Count backwards to work out the missing number.

4 3 2 1 0 -1 _{} -3

What is the missing number?

**Answer**

Counting backwards from 0, it goes:

... 0 -1 -2 -3

So the missing number is **-2**.