Another addition strategy we are working on is called counting on. If we were trying to figure out the answer, or sum, to 6+3, we would hold onto 6 in our heads and count on 3 more with our fingers. We would say, "7, 8, 9" to get our answer or sum, which is 9. This is a quick and easy way to add up smaller sums. The goal is to add sums to 20 mentally but this is a good starter step. (If this is unclear, please let me know)
Thank you for all your support at home and if you have time in the car, while cooking dinner or just hanging out, have your student practice counting by 5's and 10's to 100 and by 100's to 1, 000.