Have you already heard the expression fastoche. It's a word common amongst children which means easy. Some adolescents use it too but that doesn't mean an adult can't use it. It's a familiar word that can be used when with family and friends but not in a formal environment.
How to use the word fastoche :
C'est fastoche ! - It's easy !
Trop fastoche ! - Too easy !
As a joke, when someone knocks on the door and you answer Qui c'est ?/ Who is it ? If it's someone you know, whose voice you'll easily, the person will reply C'est fastoche ! / It's easy !
So now you have learnt a new French word and know how to use it. As you can see c'est fastoche !