Make math relevant from the very beginning. Verbalize it: "You have one shoe on. Put on the other one. Now how many shoes do you have?" Think out loud so that your child is exposed to the use of math in everyday situations. "There are three of us and I can only find two hats. I need to find one more."
Teach your child to skip count. Use a number line that he can follow forward or backward. Alternatively, try writing numbers on cut-up pieces of paper and grouping them. For example, if you are skip counting by threes, place numbers one, two and three in order, close together. Leave a space and then group cards four, five and six close together and so on. This way your child can see that three, six, nine and 12 are each at the end of a group of three. Progress with assigning a new grouping value and have your child arrange the cards himself.
Start small with addition by having your child use her fingers to count. Write an easy equation with only two numbers being added, both with a value of five or less. Have her copy the equation on paper. Explain that the plus sign means you are adding the two numbers together, and the equals sign comes before the answer. Have your child calculate the answer with her fingers. For example, if the equation is two plus four, have her hold up two fingers with her left hand and four with her right hand, then count the total number of fingers she has held up. Repeat with different equations until she is comfortable with the concept.
Write down a simple subtraction equation so that the number being subtracted from is less than 10. Have your child use his fingers to get the correct answer. For example, if the equation is seven minus three, have your child hold up seven fingers, fold down three of them and count how many are left.
Progress to multiplication using small counters such as beads to represent single units and containers such as bowls to represent groups. Write a simple multiplication equation and explain to your child that it is similar to adding, but it is in groups instead of single units. Use the beads and bowls to demonstrate. For example, if your equation is two times four, place two bowls in front of your child and place four beads in each one. Show your child that the two bowls are the "two" in the equation and each group of four beads is the "four." Once she understands this, dump out the two bowls to combine the beads and have her count them to get the answer to the equation. Repeat with different quantities of beads and bowls.
Use your beads and bowls to explain the concept of division. Choose a simple division equation such as six divided by two. Place six beads in front of your child and explain that division is simply about making groups. Take two bowls and have him place an equal number of beads in each. Once all of the beads are in the bowls, have him count the beads in one bowl to get the answer. Repeat until he understands the concept.