P.S. I have been using a free math worksheet generator for a long time. It allows us to put in several variables, then we run off as many sheets as we want. Usually make a book of “math drill” worksheets for each child. As this guy said, 10 + 10 = 20 for a long time.
Also, when you do need a “textbook,” shun the official ones. They are way overpriced and are simply part of the professor’s retirement augmentation plan. Look for comprehensive study guides. There are many wonderful ones out there and they are only as much as a regular book. No textbook surcharges and they cover the same info, often better and with less filler.
Do professors of math really write textbooks on basic math?