Easily done, same as a piece of cake. Example: Our calculus test was cakewalk. [There is a dance called a cakewalk. If you're on the right square when the music stops, you win a cake. It's also defined as something accomplished with supreme ease.]
CAKEWALK
Meaning of CAKEWALK in English
Slang English vocab. Английский сленговый словарь. 2012