Multiplication By Lines

Suppose you are tyring to multiply 13 by 12 using the Multiplication By Lines method.

You set it up and see that 13 * 12 = 156

Most people can get to this point.

What most people don't know however, is that if you were to rotate your diagram 90 degrees clockwise you will notice that a second multiplication problem is produced and answered correctly as well:

21 * 13 = 273

Rotate your diagram 90 degrees clockwise again and you will notice that a third multiplication problem is produced and answered correctly as well:

31 * 21 = 651

Rotate your diagram 90 degrees clockwise again and you will notice that a fourth multiplication problem is produced and answered correctly as well:

12 * 31 = 372

Rotate 90 degrees clockwise to get back to your original problem

13 * 12 = 156