Think of your child’s behavior as a symptom, as communication. Ask yourself what might be triggering him, what he might be trying to tell you. You have to address the underlying reasons for the behavior to make improvement.
Each time you are about to give an instruction, pause and see if you can ask him a leading question instead. In the example you gave of turning to page 25 for math, instead of telling him to turn to page 25, ask him “what page do we need to look at to do your math?” It feels much different to the child, like they have some control, and it also teaches him to think through the process, which is often a lagging skill for those with ADHD.
As for the medication, it could be the wrong dose, or the wrong medication entirely for your son. Here’s everything you need to know about ADHD medication:
Remember, ADHD is a developmental delay, so you have to meet your son where *he* is.
ADDitude Community Moderator, Author & Trainer on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism