They're also available for nearly all grade levels. There are printable middle school, high school, elementary school, and even pre-school worksheets.
Times are different these days. Kids are growing up in a world of microwaves, fast food chains, Nintendo, Wifi, iPads, along with a ton of other technical marvels.
It is amazing the difference in effort you will get from worksheet to worksheet. Granted the amount of effort may vary immensely from year to year depending on the group of students you have.
For this reason, attractive, well-illustrated worksheets with something to do will make learning fun for them. What's more, completing your worksheet will give the child a tremendous sense of fulfillment.