Read the instructions for your child's math homework given by her teacher. Make sure you pay attention to each step and read over any formulas. Ask your child for clarification if you do not understand something. Likewise, if your child does not understand a point, ask her teacher for clarification.
Practice an example question and answer to be sure you are on the right track. Verify your method and answer with both your child and her teacher to be certain you fully understand the concept.
Calculate the answers yourself to the questions your child was given for homework.
Compare your answers to your child's answers. Investigate any discrepancies to double-check that you have not made a mistake.
Point out any errors to your child, give a suggestion as to what step of the problem may be incorrect and have her reattempt the question. Compare again, and repeat until your kid grasps the concepts and is getting all of the answers correct.