Multiplication table sheets help you memorize multiplication facts, making them a good learning activity. Practicing or doing drills with a multiplication table sheet every day is a good way to learn multiplication.
MathIsFun.com has online exercises to help you train yourself to remember multiplication facts. One way to practice is to look at a time table grid and choose one row. Point to each answer in a row, and say it out loud. Cover up the answers in the row, and see if you can repeat the answers from memory. Once you have a row memorized, move on to the next row.