Use flashcards. Make multiplication cards for each number set. Although this may seem tedious, the process of making the cards will actually help you to learn them. Once you’ve made them, spend some time each day studying until you know them all. Focus on one number set at a time. When you go through the cards, put the ones you get wrong back into the pile so you see them multiple times.
During 1st grade, children will then learn addition and subtraction facts, two-digit numbers, some adding and subtracting with two-digit numbers, and some basics of measuring, time and money.