takes the cake

Does "take the cake" mean something best or worst done so far like the following? What are the similar expressions?

*worst
A:He cheated on this math exam again.
B:He so takes the cake.

*best
A:This soup takes the cake.
B:Do you want to go for another?

rtg-96

You're very close to the correct meaning, Keannu, but not quite 100% there. Here is a site that explains the phrase. If you read it and try two new sentences, I'll be happy to check them out.
Take the cake

It's worth noting that in Br Eng the more common form of this idiom is 'to take the biscuit'. (Still, that's how the cookie crumbles.)

b

Yes, this is a US-only expression. It has no meaning in British English. In Britain we would say "that really takes the biscuit!" Mind you, it's not very commonly used nowadays.

take the cake means to be good or outstanding): steal the show
(to be particularly bad or egregious): take the biscuit (British)

I'm a Brit who uses "take the cake" a lot.