If your adolescent is struggling in math you need to know for sure that he knows his basic math facts to an automatic level. By “automatic level,” I mean he does not have to expend mental energy remembering them. If he does not, then he is unlikely to do well in higher level math courses like pre-algebra and algebra.
When he begins using integers, he must learn the rules for using both positive and negative numbers when he adds, subtracts, multiplies, and divides. If the number facts are automatic, then he will only have one level of thinking to do. (How does this negative sign change the way I work with these numbers?). But if he is still struggling with the basic facts, he must think on two levels. (What do these numbers mean? What do these signs mean?) He may wind up making errors he might not otherwise make.
When dealing with basic math facts, a calculator will not solve the problem. The calculator just adds yet another level of thinking. (What do these numbers mean? What do these signs mean? How do I enter this into the calculator?) He is better off without the calculator.
Test your child’s skill with basic facts. See how long it takes him to go through a stack of multiplication flash cards answering each one correctly. If he takes a long time to get through the stack, he needs to practice some each day. He needs to be able to answer them quickly almost without thinking. This is true for adding, subtracting, multiplying, and dividing numbers up to twelve. Continuing to practice—even five minutes a day—will increase his speed. This will help him tremendously in whatever math course he is taking.