Lori,

It sounds like your younger son doesn't quite have the abacus in his mind yet. Perhaps, when the lesson says "do it in your head", have the abacus in front of him, but challenge him not to touch it. Have him mentally move the beads to create the answer. My daughter needed this step.

How is he when playing card games? Does he use the abacus then? If not, do! Also, have the older son play card games with the younger son.

In regard to moving on or pausing the lessons, pay close attention to the objective of the lesson. Level B Lesson 76 objective is "To mentally add 2-digit numbers". It doesn't say "be proficient in adding 2-digit numbers" or "have mastery in adding 2-digit numbers". It just says to do it and work with it.

The objectives are very important to you as the teacher. They will tell you when you are practicing (Lesson 77), discovering (Lesson 78), learning (lesson 79), recognizing (Lesson 83), or understanding (Lesson 88).

I do hope this helps both you and your son. Have a great day and play a math card game!

Kathleen