How to Easily Memorize the Multiplication Table I Math Tips and Tricks with Art Benjamin

The multiplication table seems to be quite imposing. After all, it contains hundred facts. Look at it. How could any child be expected to memorize that? And yet, claim that more than half the table takes no time to learn. It's obvious how to multiply numbers by one and multiply numbers by 10. And multiplying by two is just an easy addition problem, right? 6 * 2 is just like 6 + 6 12. So if you eliminate 1, 2, and 10, we've reduced the problem to memorizing 7 by7 table which has only 49 entries. In my experience, the stumbling block for students memorizing the multiplication table is learning their multiples of three and four. Once you know that, there's really not that much more to learn. teach students their multiples of three by first counting by threes. 3 6 9 12 and so on. And then we do it faster. And then we do it faster. And eventually it's 369 12 18 214 27 30. Then I'll ask them 3 * 1 is 3 * 2 is 3 * 3 is in order. So they they associate the multiplication problem with the sequence they've just learned. And then we do it in mixed up order until eventually they know their threes table. teach the multiples of four in the same way. We learn to count by fours and eventually do it very quickly. 48 12 16 20 24 28 32 36 40. And that leads to learning four * 1, four * 2, four * 3 in order, then eventually out of order. And learning the multiples of five is even easier since every multiple of five ends in five or zero. There's also simple trick to multiplying by nines. You'll notice that the multiples of nine have the property that their digits add up to the number nine. Right? like 9 * 2 is 18 and 1 + 8 is 9. 9 * 3 is 27. 2 + 7 is 9. The digits of 36 3 + 6 add up to nine and so on. Also, the first digit is one less than the multiplier. So 9 * 2 begins with 1 and 9 * 3 27 begins with two. 9 4 36 begins with three and so on. So problem like 9* 4 since it will begin with three and it will end so the digits add up to 9 we can figure out the second digit which is 6. So 9 * 4 is 36. Once we know the multiples of 1 2 3 4 5 9 and 10, this reduces the multiplication table to tiny 3x3 square. And people find it easy to learn the onedigit squaring problems. 6 * 6 is 36, 7 * 7 is 49, and 8 * 8 is 64. So it just comes down to learning three hard facts. 6 * 7 or 7 * 6 is 42. 6 * 8 is 48. And 7 * 8 is 56.