u can try calling 65659390 or 96366996 (Mr Koh) tuition centre, Jurong area
I'm in Ngee Ann poly now. from my own experience Mr Koh and his tuition centre is excellent in helping students in science, math, and POA. personally i science(PHY/CHEM), Math, and POA when i was in sec3, all the way up till my O's.
some parents feel that 1 to 1 tuition would be better, but trust me, you won't regret sending your child to his tuition centre. however, his fees are considered a little more expensive than others out there. but he assured me that i will get and A in my O's (i thought he was arrogant back then, but it did came true and i got As for every subject he taught me)
he had a unique way of teaching, by incorporating friendship and humor at sometimes but extremely strict in attendance and attentiveness.