Help the child understand what multiplication and division are. In order for the child to completely understand how to do multiplication and division, he must first understand the reason for multiplication and division. Multiplication is simply repeated addition. Explain that multiplication is a quicker way of adding numbers. Division is repeated subtraction. Explain that division is a faster way of subtracting.
Introduce multiplication and division separately. Multiplication and division are the first step away from basic adding and subtracting. Introducing multiplication and division separately ensures the child becomes comfortable with each section. This also ensures that he is able to focus and successfully learn each section.
Be repetitive. Give the fourth grader a few multiplication or division problems. Allow the child to work on the problems. As you introduce more problems to the child, continue showcasing older problems. For example, after you give the child a new worksheet, ensure that older problems are included on the worksheet along with the new problems. This keeps the earlier problems fresh in the child's mind. Repetitive problems also give the child familiarity, which acts as a brain trigger. When the child sees the familiar problem, he remembers how to solve it and apply that method to newer problems.
Use visual aids. Simple multiplication and division visual aids are designed to give children a hands-on experience when learning each section. For example, take three action figures and place them in front of the child. Have the child place two pieces of candy in front of each figure. Have the child count all the candies in front of the figures. Explain to the child that two plus two plus two is six. Write the equation down on a piece of paper. Explain to the child that two times three -- the adding together of three groups of two -- is also six. Write the equation down next to the first equation. Frequently use visuals to help children understand written equations. Use the same scenario except with division problems.
Implement mental math. After the fourth grader successfully answer multiplication and division problems with the use of visual aides and repetition, start implementing mental math. For example, ask your child a question such as "If I have three cookies and I give two other people three cookies, how many cookies do we have in total?" After asking the question, ask the student what the multiplication problem would be and then ask for the answer to the equation. Do not allow your child to write out the problem to solve it.