this is interesting clip. Don’t cheat and don’t use a calculator! 
Love the “Inteligent” tag.
I got the first question right (adding in my head and saying the digits aloud), but the bonus ones are too tricky for me. I guess I’m not that clever.
Clever than what?
Than all of the people leaving comments, clearly.
And it’s ‘cleverer’.
ETA: Or ‘then’. With a preceding comma.