Another thing to look out for is what the pupil will need to solve the worksheets? Does the worksheet require the use of crayons? Does it require other things like a pair of scissors, glue and so on? Before you buy worksheets, make sure to check if they have been created to suit the geographical location that you reside in. The language and usage of words differs from country to country. It is no point buying a worksheet which is designed for children in the US for children residing in India. Also see if the worksheets involve just one way of teaching or multiple ways. Do the worksheets involve short assessments? Does it have some activity built in; does it involve elements from the childs surroundings?
Math concepts can also be reinforced for the children throughout the day on a regular basis. Try placing an enlarged number 12 above the 12 on the clock and label it "lunch time". Label your clock with as many of these types of labels that you can. This will help the children to recognize the way the clock looks when it is on the hour. Make sure to point out the clock when it is time for lunch by saying, "Look at the clock, it is time for lunch. See the little hand is on the 12". You can also incorporate math through songs. If you are learning about monkeys, make it a point to sing, "Five Little Monkeys Jumping on the Bed". The same concept can also be used when you are reading books to preschoolers. There are plenty of books that incorporate counting into their story and will follow the theme you are teaching. Math is a concept that children will have to use for the rest of their lives and that will be continuously taught in school. By starting off their education with fun math activities, you can get them started with math the right way.