Teach your child how to add and subtract numbers by using the finger method. Hold up your fingers as you count. For example, to teach your child that 1 plus 1 equals 2, you would hold up one finger with your right hand, say the number and math sign, hold up another finger with your left hand, say the number and the equal sign, and then hold up both fingers as you exclaim the answer.
To teach your child what each number looks like, do an exercise on paper. Tell your child to repeat after you as you write down the math problems while you say them. As you write down the problem "2+1=3", say the numbers and sign after each number in order of where they are written. Then, point to each number and sign in order to have your child repeat what you had said. If your child gets stuck, help him. Move on to a new problem. Over time start pointing to the numbers and signs without letting your child know what they are and see if he can supply the correct terms. When you think your child is ready, stop writing down the answers to the problems and have your child tell you the answers.
To get your child used to the school setting, start adding and subtracting numbers on a blackboard. Do the same exercise as step 2 but only on the blackboard. The new setting will most likely excite her and make her more eager to learn. Remember to have patience as your child is learning.
Give your child visuals by adding and subtracting objects. For example, hold out two rocks, take away one, and then your child will see there's one rock left. Say the numbers as you add and subtract the objects. Have your child add and subtract a few objects when you feel as though your child is ready, saying the numbers as he goes along.
For a little treat, subtract cookies or candy with your child. For example, hold up three small cookies, eat one, and then ask how many cookies you're left with. If your child gets the answer right, let her eat a cookie and ask her how many cookies you are left with now. You can start off with 10 cookies if you like and subtract the cookies in this fashion. Don't use this method too much though, for you don't want your child to get unhealthy while learning math. You can also subtract more nutritional treats if you want, like cooked beans or broccoli.