Counting using positive and negative numbers
In a nutshell
Counting forwards and backwards using both positive and negative numbers is easy when you use a number line. Doing so creates a sequence.
Counting using positive and negative numbers
To count forwards and backwards through zero with negative numbers, using a number line, use the following steps:
- To count forwards, move up the number line in the increasing direction.
- To count backwards, move down the number line in the decreasing direction.
Example 1
Count forwards five from −3.
Find your starting point: −3.
Count up three in ones until you reach zero.
Then, continue up a further two, taking you through zero into the positive numbers until you reach 2.
−5∣−4∣−3∣+1↷−2∣+1↷−1∣+1↷0∣+1↷1∣+1↷2∣3∣4∣5∣
Example 2
Count backwards in threes from 6.
Find your starting point: 6.
Count down in threes until you reach zero.
Continue through zero, counting backwards three each time.
The numbers 6,3,0,−3 and −6 form a sequence that is decreasing by three.
−6∣−3↶−3∣−3↶0∣−3↶3∣−3↶6∣
There is no end to this counting. The negative numbers, just like the positive numbers, continue on forever.