Rational Numbers

There are situations in which Whole Numbers are not enough:
- When a division is not exact.

- When I want to express parts of a unit

In these situations we need fractions. When we add the fractions to the Whole Numbers, we obtain the Rational Numbers, Q.
Now we have these sets of numbers:

We represent these in the straight line too. 

For example, to represent 3/5:
- We draw a line from zero.
- We draw 5 marks at equal distance with a compass.
- We connect the last mark with 1 and draw the parallel lines.

Exercise: Represent these numbers in the number line: -7,  5,  1/5,  -2/3,  7/3,  3/2,  -9/5