As already mentioned free coloring pages are a great way to teach your child all sorts of things, numbers for example. There are different ways this can be done, one way would be to simply have the number somewhere on the page, such as the number 10, and then somewhere else on the page would be an object or animal cleverly twisted into that number. There could also simply be 10 of something on the page, you can get your child to color the page in and then count out how many apples for example there are, which will obviously correspond to the number on the page.
There are plenty of wonderful options to choose from when it comes to getting the right color pages for a child. You can choose designs suitable for children of a specific age; for instance, the ones for very young kids have large and simple patterns unlike the ones for older kids. You could also get pages that feature the child's favourite cartoon characters. Eventually, the child can move onto creating original drawings that help express his or her personality.