Hey there! :D
A rational number is a number that can go into a fraction or ratio, or that is a repeating decimal. 1/3, 5:2, 7.8787878787.....
An irrational number is a number that cannot go into a fraction or ratio, and it's decimal's are not repeating. Like π, √5, 6.785321478 etc.
I hope this helps!
~kaikers