Like other experienced teachers, I've taught the same concepts and skills to students so many times that I've developed a huge repertoire of activities that I can build into my instructional time. I have activities that provide more scaffolding if the kids didn't really seem to understand the lesson, and activities that will extend student learning if what I taught was too easy. I have activities that will take a long time if my lesson ends early, and activities that can be done quickly if my lesson takes too long.
Make numbers a part of your everyday routine. Your child might not like addition, but he may enjoy counting the number of stop signs on the drive to school or the number of stairs on your porch. Lead by example to encourage your child to think of math exercises as a part of his daily routine.