Going back the original question vs. direction this post has taken. My older DD has language processing LD and while learning math operations with numbers wasn't a problem for her word problems were a HUGE issues. I'm not suggesting your son has an LD but I figured I could share what i did with her. These are a basic idea's but sometimes basic suggestions gets overlooked. Read the problem out loud if you can (hard during a test), underline the important numbers & their units, cross off the unnecessary verbiage, circle the words that describe the operation. If it's homework trying to explain the problem and/or what you don't understand to someone else even if it's the cat or dog often works wonders. Basically slow down and treat it like a puzzle to be decoded and practice, practice, practice.
I love the idea of having him try to write his own word problems.
Drawing sketches helps, too-- though this gets to be a better strategy in algebra and beyond. Most scientists I know
always work problems this way. It helps, sometimes, to draw a picture and label it with the values from the "word" problem, and then convert directly into symbolic mathematical representations from there.
Not always time in a pinch on an exam, of course-- but I suspect that this is behind the notions implemented in Common Core regarding "visual representations" of math. It does help when it comes to applied problem-solving.
