You can turn substraction into fun

Subtraction, Your Kids and You
Math is likely one of the most difficult things any parent must contend with when helping their child understand mathematical concepts. There is a simple way to make subtraction easy for kids. Kids are most likely to retain images they see longer than those they must visually create. The first time children hear the word "subtract", their minds immediately grow murky with misunderstanding of what it means. Yet, pre-school age children can be taught subtraction as soon as they are able to create words. Teaching the "how" is much easier for parents than the "why".

What Kids See Is What They Subtract
A child can learn subtraction as young as age three. Use subtraction as a learning curve in each day's activities. For example, if a child is playing with several toys, have them remove one to show them what subtraction means. Once they understand that subtraction is merely deducting a unit from a group, the idea of what subtraction means becomes clearer. Use subtle instruction to get the idea of subtraction across rather than formal teaching. Formality at a very young age is certain to be a huge repellent for educational instruction later. Make subtraction as much fun as possible.