Start with the easy ones (1, 2, 5, 10), then use the rule that order does not matter: if you know 3 × 7 you already know 7 × 3. That leaves 36 distinct products between 2 and 9. Practice a few at a time, in short sessions of 10 to 20 facts, and let Practice repeat the ones you miss: it gives them more weight when drawing.