But if you can add and subtract 3-digit numbers, then adding and subtracting 4-digit numbers is not exactly a challenge for an HG+ kid...and that's what's coming up.
I know what you mean. Looking through the next few Singapore math books it's obvious that DS can already do quite a lot from the next few levels. I kind of like it
DS is at 3A as well, I think there are only one thing he doesn't know in 2B are gallons, pint, ... one of these days we will look at it. The really new thing in 3A is multiplication of big numbers such as 287*7 and long division. If your son doesn't know the table than taking break from Singapore sounds like a good idea, otherwise skip things he can obviously do or let him choose what he wants to do (that's what we do, we leave books of different levels lying around he is free to do what he wants or nothing if that's his choice).
This week I got Primary Grade Challenge Math by Edward Zaccaro and it looks like a good book. There are things my son knows really well, but there are a few concepts which will be new to him. Level 4 problems look pretty nice, challenging, but doable.
Life of Fred Fractions by Stanley Schmidt is a nice funny book. Lots of multiplication and division though, but you can always help your son with that and worry about the concepts only.
