One issue many of them were having however was sweeping forwards or back along the grid when skip counting, adding or subtracting. Unfortunately many of them don't quite understand number patterns well enough yet to realize when they've skipped a decade, etc.
I decided to give them a colored visual to help them connect each end and hopefully reduce simple errors. So far it seems to be working. I never explained how to "match" the colors when sweeping, but most picked up on it, and have been making fewer errors.
It also helps them to correct a sweeping error, such as if they are sweeping back from 41, which is yellow, but land on 30, which is pink, they realize this can't be right. I'm hoping this will help some of them notice that patterns more as well.
I've also made a few which highlight skip counting patterns, as well as having the 0 and 1's columns colored. My next project is to do some 200's charts for my second grade friends who do fine going forward, but tend to get loss when needing to go backwards for subtraction problems.
If you are in need of a hundred's chart, mine came out of a Scholastic book, however most math curriculums have one ready to copy and you can find plenty by just googling.
Have you ever modified something for your students (special education or not) that has helped them better understand a concept or complete a task?