Math help?

You guys have been AWESOME about recommendations for the kindergarten crowd so I thought I’d come here for some advice! My kindergartener has an IEP for speech and is making awesome progress (SLP at school twice weekly and private in home once weekly to supplement). This has caused a bit of a delay in other learning, I think, because he’s putting tons of energy into speech.

You all recommended Bob books and his interest and literacy have SKYROCKETED because of it! Still a little behind but on the right track. Where we’re struggling is math now—his teacher and I have realized he just isn’t quite comprehending it. Can count to 30, can count down, but really struggles with understanding basic addition and subtraction. I’ve been using board games and dice games and little pieces of candy, etc, to try and make the connections but still struggling! We’ll be doing a summer school program at the recommendation of his teacher to help boost this but I want to be proactive about it. Luckily he really loves “doing my math” so isn’t frustrated but just not getting it! Any programs or workbooks or even apps that you might suggest for basic, fun addition and subtraction help?