1cm graph paper with blue lines.
I buy it from Miller’s Pads and Paper when they are at a local convention. I cannot find 1cm graph paper locally, and the 1cm graph paper I bought from Amazon had black lines which made it difficult to use since it was difficult to see the numbers.
I re-write the problem so that eliminates some of the writing.
I have just recently started letting him use Dragon Naturally Speaking for his written narrations while he continues to work on typing. I haven’t thought about using it for math but speech-to-text would be the next step.