Games that require you to count the number of spaces you can move develop basic counting skills. Games such as Chutes and Ladders and Candyland also help with subtraction as they require players to go back spaces. Counting the number of dots on a pair dice helps develop counting and addition skills as well.
Take every opportunity to subtly include math skills into everyday life. When cooking together, ask simple questions such as, "If I have two eggs, but I should have three, how many more do I need?" At the grocery store, ask your child to get five apples and then ask him how many you would have if you put two back. You can even incorporate counting and adding into the laundry. Have your child count how many shirts each person in the family has or how many more pants he has than his siblings.
Recognizing numbers is an important skill as well. At 5 years old, your child can start working on recognizing them when they aren't directly in front of her. When out in the car, ask your child to keep her eyes open for numbers on road signs, storefronts and billboards. Have her point out the number when she sees it. You can also tell your child a phone number and have her dial it.
Use an empty notebook or have your child create his own book with blank paper for this project. Make each page a letter of the alphabet and then have your child cut out images from magazines that correspond to each letter and its number position in the alphabet. For example, cut out one image for "A", 10 images for "J", 15 for "O" and so on. This project also helps develop reading skills and motor skills.