We love Singapore Math and use it at home. The one criticism I would make is that we find it doesn't explain new concepts very well. I mean, the pictures are good to visualize this is multiplication, etc. But I just told my son how to carry numbers or things like that.
Second grade is where they need to know their math facts for subtraction and addition. You could also consider throwing in a little workbook on Kumon, which is drill and kill. Just a little since it does get boring but it is very good at getting your math facts down.
