piece of cake 小菜一碟，轻而易举的事

　　For me, math is just a piece of cake.

　　数学，对我而言，就是小菜一碟。

　　Don't worry, breaking up with him is just a piece of cake.

　　别担心我，和他分手对我来说，轻轻松松。

　　疯狂练习吧！