A student who is behind in maths is almost never behind in this year's work. They are behind in something from two years ago that this year's work is standing on, and no amount of repeating the current chapter will fix it.
So every student starts with an assessment, which is one free session and a written page telling you exactly where the gap is. Sometimes the answer is that there is no gap and the child needs practice and confidence rather than tuition, and we say so and charge nothing.
Everything after that is built on the gap rather than on the term.