Cross Zero When Counting Backwards and Forwards

These sequences are examples of counting up - the numbers increase as we move from left to right.

0  1  2  3  4  5  6  7  8  9  10  11...

60  70  80  90  100  110  120...

We can also count back.

When we count back the numbers decrease.

11  10  9  8  7  6  5  4  3  2  1  0... 

120  110  100  90  80  70  60...

What happens when we count below zero?

When we count below zero we call the numbers negative numbers.

-4  -3  -2  -1  0  1  2  3  4  5

The numbers to the left of zero are all negative numbers.  

 The negative symbol ( - ) before each number tells us that the number is negative.

Although the digits are getting bigger (2, 3, 4), they are actually decreasing the further away from zero they move.

So, -4 is one less than -3

We can decrease in multiples of numbers in the same way we increase.

-12  -9  -6  -3  0  3  6  9...  (3 times table)

Now, why don't you have a go at some questions?

Check back to this page if you find it tricky by clicking on the red help button on the screen.