As of 2015, SuperTeacherWorksheets.com and Math-Drills.com provide free worksheets with answer keys for educators. Both websites feature worksheets that are available to download in PDF format, and SuperTeacherWorksheets.com features worksheets for many subjects, including math, reading and science.
Find free worksheets with answer keys on SuperTeacherWorksheets.com by choosing a topic on the left side of the homepage and then clicking View PDF by a worksheet on the next page. The downloaded file includes the worksheet and the answer key.
Click on a topic on the homepage of Math-Drills.com to find its free worksheets with answer keys. Then, click on a worksheet on the following page. Finally, click Open/Download the PDF Worksheet to view.