A rational number is a number that can be made by dividing two integers. An integer is a number that doesn't have a fraction part.
1. 2.4 - rational
2. 74 - rational
3. 17.3333333… - rational
4. π -irrational
5. there is no number
6. –18 - rational
7. there is no number
8. 87.125 - rational
9. –30 - rational
10. –8.3 -rational
11. 58.25 -rational
12. 121 -rational
13. 4.5 -rational
14. 3 7/10 -rational
As you can see, most numbers are rational. But, when you come across pi or when you have a decimal that goes on forever without repeating (like some square roots), it tends to be irrational.