What's 9+10+21? (Use your brain!)
Cause if you say 40, it's wrong. Mindblown.
Crazy You are
40 explain why it isnt?
$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}}{\mathtt{\,\small\textbf+\,}}{\mathtt{21}} = {\mathtt{40}}$$
9+10=21
21+21= (Wait for it...) 42!