Learning English is a piece of cake!
“A piece of cake” is a common idiom that means “extremely easy to accomplish.”
Examples:
“Exams in this class are a piece of cake, so I’m not even going to study.”
“After studying Latin, learning Italian was a piece of cake.”
“I thought babysitting by nephew would be a piece of cake, but he’s a little terror without his parents around!”
This idiom might refer to how easy it is to eat a piece of cake, or it might have its origins in a 19th century dance done by Black Americans, called a “cakewalk,” in which the most graceful couple would win a cake. Now, the term “cakewalk” means “something very easy to do,” exactly the same as “a piece of cake.”
Speaking of easy things and sugary snacks, if you want to say how effortless something is, you can also use the idioms, “Easy as Pie,” or, if you’re talking about something both easy to do and negative, you can say it’s “like taking candy from a baby.”
“You make walking on stilts look as easy as pie!”
“The bank doesn’t have good security; robbing it will be like taking candy from a baby.”