This term we are doing idioms this is my one on a piece of cake.
Piece of cake
Figurative meaning:
Something that is easy
It came from the 19th century when people competed in a competition by walking in a circle elegantly and then they received a piece of cake.
My brother and I competed in a reading contest, it was a piece of cake, and I won by a landslide!
P.S. The story is fake I made it up