Go Shopping! : You can cater this to all different ages. For young children, you can do a 'mock shop' and let them pretend to go shopping in a pretend store (your kitchen). Label certain items with easy to read prices and print some pretend money for them to shop with! For older children, you can let them help you in the actual grocery store with a specific shopping list. You can even set specific spending limits and give a specific amount of items and let them determine what they can afford, etc.
Another strategy involves allowing your child to spend some time on a computer playing math games. The computer can be a wonderful resource that supports math and other subject area skills. Software is available that will measure a child's math skill level.
In addition to mental math activities, children should be given grade level mathematics workbooks to strengthen their math skills. Parents should have these books and other subject content books at home for additional practice and homework. These can be purchased from bookstores, teacher supply stores and multiple-purpose department stores where school or office supplies are sold.
As children become more confident in their math skills, give them worksheets one grade level above their current grade. Help them if necessary, but when students become successful in the upper level workbooks; their confidence will really improve. The seed will be planted early and parents can watch as it grows.