no prizes for guessing

US /noʊ praɪzɪz fɔr ˈɡɛsɪŋ/
UK /noʊ praɪzɪz fɔr ˈɡɛsɪŋ/
"no prizes for guessing" picture
1.

used to say that something is very obvious and easy to guess

:
No prizes for guessing who ate all the cookies.
When the lights went out, there were no prizes for guessing what happened next.