Try to determine if there is a need for a math tutor for your child. One way to do this is to go and talk to the teacher in order to get a better understanding of where your child is as well as to determine what the teacher thinks you should be doing to help your child.
If you are looking into getting a math tutor you may want to consider all of your options first. It could be as simple as finding someone in the class who has a better understanding of the material or simply going after and seeing your teacher so that they can better explain the material.