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Multiplication and division by 2 and 5 correspond to each other. Multiplication by 11 is shift-and-add. There are many such tricks.
by wizzwizz4 2y ago
Multiplication and division by 2 and 5 correspond to each other. Multiplication by 11 is shift-and-add. There are many such tricks.
- Dylan16807 2y agoThe first one doesn't help with remembering times tables. The second one is outside the 1-10 times table we were talking about.
- wizzwizz4 2y ago6 is 2×3, so 6×5 = 30. Likewise, 17 = 2×8 + 1, so 5×17 = 85.