# 2-8 Number Line

### Lesson List

The diagram above is a number line. A number line shows numbers in order. A number line has arrows because it keeps going and going in both directions. All numbers can be shown on a number line.

Fill in the missing numbers on the number lines below.

 <--0-- -- -- -- -- -- -- -- -- --10-->  <--9-- -- -- -- -- -- -- -- -- --19-->   <--17-- -- -- -- -- -- -- -- -- --27-->

You can use a number line to add and subtract numbers.

For example, to find the sum of 5 and 6, first find the 5 on the number line, then move to the right 6 numbers. You end on the number 11.  So, 5 + 6 = 11.

Use the number line below to find the sum of two numbers.

 4 + 4 = 3 + 5 = 1 + 4 = 2 + 7 = 5 + = 8 2 + = 5 + 6 = 9 + 4 = 7

You can use number lines to subtract. To find the difference between 9 and 4, start on the nine and move to the left 4 numbers. You end on the number 5. The difference between 9 and 4 equals 5 or 9 - 4 = 5.

Use the number line below to find the difference between two numbers.

 9 - 5 = 8 - 4 = 7 - 3 = 6 - 2 = - 7 = 2 - 4 = 2 - 3 = 5 - 6 = 7