Can anyone give me info on SOS(Math)? Like what you liked/disliked about it? Did it explain topics in depth? I can't decide whether to buy SOS (Math only) or to buy TT. I want something DVD or computer for math for a back-up (I'm buying Singapore) because DD has certain days with math that its just easier for me & her to have a computer tutor for the day. And she loves the computer. Any information is greatly appreciated.