# Poll: the sum(7,9)

Jim Hurley jhurley at infostations.com
Tue Mar 15 08:38:49 CST 2005

>
>What a fascinating question! I had to think for a minute to try and
>analyze how I do that sort of mental arithmetic, but in the end I
>realized what I do.
>
>I seem to have a visual stack that goes up to 10, so I put the 9 into
>stack, then move 1 from the 7 to fill the stack, leaving me with 10 in
>the stack and 6 left over. I guess this is #1 but with more of a
>number-line visualization rather than fingers :-)
>
>HTH,
>Sarah
>

Sarah,

I am also digitally oriented. I envy those people with memories which
allow them to simply snatch these results from their memory bank.
Mine is bankrupt.

I also apply a similar digital technique on subtraction. For example:
subtract 9 from 17. Subtract 7 from 9 to get 2; that's easy. Then
subtract 2 from 10 to get 8. Therefore 9 from 17 = 8. Pathetic I
know. I have even forgotten portions of the mutilation table. My
transition into senility is very smooth.

(Do this with your fingers in you lap and you have a laptop computer.)

Jim