Children have shorter attention spans than adults. It's important to pay attention to your child's individual stamina. Some kids will only work in five-minute spurts at first. You can slowly increase the length of time your child stays focused to increase their stamina over time. Making sure the workbooks are not too easy or too difficult will help your child stay on task. Fifteen- to 20-minute sessions are a good end goal (perhaps a little longer if your child is older).