I just saw the 9x finger trick on Pinterest. I've used that for as long as I can remember, but it made me think of another trick.
Brock was working on these one day and he started explaining a new way to figure out the 9x. I had never heard of this and as far as I know he figured this out on his own, if he saw or heard it somewhere he's keeping it a secret. Either way it is quite helpful, a couple of more steps than the finger trick, but good problem solving practice anyway.
Let's take 6x9. Your tens place number will be one less than the factor that is not 9 (in this case 6), so that would be 5. Your ones place number will be the difference between 10 and the number nine is multiplied by so that would be 10-6=4. That makes the product 54. It only works up to 10x9; but pretty cool, huh?
Numbers are just plain cool. Wish I thought that when I was in school! I hated math then, but now appreciate it so much more!
ReplyDeleteA neat little trick, I had to teach the finger trick to my Judith, she struggles to remember the times tables.
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