This is the foundation.
When a child struggles in their early years, it doesn't get better.
I've seen so many parents wait, thinking that their child will catch on. Unfortunately, it rarely happens. The more likely outcome is that your son or daughter continues to get bad grades, gets more and more behind and starts to hate math.
The best thing about getting tutoring right when the problems start is that tutoring can be a short term undertaking. Often we only need 6 or 8 sessions to get back on track.