to be quite good at something = can do it
YES
not mad about it = like
NO
I'm not mad _____ fishing.
ABOUT
She isn't really ____ cooking...
INTO
Peter is very keen ____ science!
ON
Sarah is quiet good _____ dancing.
AT
My grandfather isn't a big fan ____ playing computer games.
OF
We are interested ____ technology.
IN
to be keen on = like
YES