Worried parents ask me this question frequently, usually just after their parent-teacher interviews or after receiving a mid-term report card.
If your son is failing half way through the term, he may be able to turn things around but as a parent there are two steps you need to take immediately.
First, your son and/or you need to speak to his teacher a.s.a.p. in order to know what mark he needs to average over the rest of the term on his quizzes, tests, and final exam to be able to pass the course. If he can maintain that average, he will pass the course.
Second, you and your son need to find out why he’s not passing. - Study Skills: Is it because he is not doing his homework? - Not understanding: Is it because he’s memorizing the math? - Gaps in Past Math Knowledge: Is it because he's weak in areas of past math?
Once you know what’s holding him back, the next step is to strengthen those weak areas as much as possible before the end of the term. Ask his teacher for recommendations on how to do so.
Important to know: Over the years, I have observed that sometimes a teacher who sees that a failing student is really make an effort in the second half of the term - being diligent about doing homework, coming in for extra help regularly, obviously working hard and trying their best – may choose to give the student the benefit of the doubt when calculating the final mark. In other words, for example, if the student ends up with a final overall mark of 48% or49%, the teacher may increase that grade to 50% on the basis of all that hard work rather than let the student fail the course. That only happens once in a while but it illustrates another possible benefit to really working hard, and making sure the teacher knows it, during the rest of the term.
Preparing your son for his next math course: Make sure those weak areas are really strengthened before your son starts his next math course, otherwise the exact same problems will come up again next year but the results will be worse.