Writing numbers down on a Number Line makes it easy to tell
which numbers are bigger or smaller.
|Negative Numbers (-)||Positive Numbers (+)|
|(The line continues left and right forever.)|
Numbers on the left are smaller than numbers on the right.
- 5 is smaller than 8
- −1 is smaller than 1
- −8 is smaller than −5
Numbers on the right are larger than numbers on the left.
- 8 is larger than 5
- 1 is larger than −1
- −5 is larger than −8
Try this interactive number line (click to mark):
You can also try the zoomable number line.
Example: John owes $3, Virginia owes $5 but Alex doesn't owe anything, in fact he has $3 in his pocket. Place these people on the number line to find who is poorest and who is richest.
Having money in your pocket is positive.
But owing money is negative.
So John has "−3", Virginia "−5" and Alex "+3"
Now it is easy to see that Virginia is poorer than John (−5 is less than −3) and John is poorer than Alex (−3 is smaller than 3), and Alex is, of course, the richest!
Using The Number Line
We can use the number line to help us add. We always move to the right to add.
We can use the number line to help us subtract. We always move to the left to subtract.
Absolute Value means to think only about how far a number is from zero.
For example "6" is 6 away from zero, but "−6" is also 6 away from zero.
So the absolute value of 6 is 6, and the absolute value of −6 is also 6