Teacher content in the end, is one good at multiplication? (6)
I believe the answer is:
rabbit
'one good at multiplication?' is the definition.
(as in breeding like rabbits)
'teacher content in the end' is the wordplay.
'teacher' becomes 'rabbi' (Jewish teacher).
'in the end' says to take the final letters.
The final letter of 'content' is 't'.
'rabbi'+'t'='RABBIT'
'is' acts as a link.
(Other definitions for rabbit that I've seen before include "Person poor at games" , "Bunny; chatter idly" , "Game" , "Chatter; poor games-player" , "Talk at length" .)