Practicing addition with your child is a great way to get him excited about math! Young kids who are beginning to learn addition often need to see a visual representaion of any given problem. Many kids will use their fingers and toes, but make things more fun by using counters. You can use pieces of cereal, beads, mini marshmallows or anything you would like. Kids love switching things up with large-sized counters, so bust out pillows or purses to make learning addition even more fun.
In KS2 children are taught that decimals are another way of writing fractions. The hundred number square is a really good way of showing children the equivalence between fractions and decimals.