We've been using Singapore math with my 1, 2, and 5 graders. Up to now, I've been winging it as far as teaching the lessons. I'm getting ready to order level 4a for dd11. How essential is the instructor's guide for that level? I don't want to spend the extra $ if I don't have to, but I also don't want to miss something we need just to save a few bucks. TIA!
I find the mental math drills in the instructor's guide alone are worth the price. They have really improved my children's mental math skills.
