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.
Coloring pages can provide enrichment by providing pictures of numbers, letters, animals, and words, so that your child will expand their knowledge in a number of areas. Your child will receive the greatest educational benefit when the coloring pages bring all of these elements together, such as when there is a picture of an animal with it's name written on the page, or when numbers are shown with the name of the number written out, or even a two_sided coloring page with one side showing the letter, number or word, and the other side of the page depicting an animal whose shape resembles the letter or number on the previous page. Take for example a coloring page that has a number one, along with a giraffe that is reminiscent of a number one in it's shape. Your child will not only have fun coloring the number and animal, but their lesson will also include writing the number one and being introduced to a giraffe.