Foo - How do you do your subtraction?

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jschen
06-02-07, 01:30 AM
Okay, following up on a question I asked over a year ago...

Just for amusement, let's try something. I am posting two numbers below. Try to subtract the second number from the first either in your head or on paper (no assistance from computer/calculator/abacus/counting beans/etc).

314.159
271.828

Which way did you work? Left to right, or right to left?

jschen
06-02-07, 01:34 AM
Aforementioned thread (http://www.bikeforums.net/showthread.php?t=164172) from over a year ago.
ms.gio
06-02-07, 02:37 AM
Answer: 42.331

Thanks jschen for making me doing simple substraction at 3:45 am. To be honest, that was a little hard for me to do at this hour...and I used to be an engineering student. :rolleyes: Goodness, I need to get to bed.

Nicodemus
06-02-07, 03:56 AM
me3h. i go for ride now
bitingduck
06-02-07, 07:23 AM
L to R in my head, R to L on paper
polara426sh
06-02-07, 07:27 AM
pie
atomship47
06-02-07, 07:29 AM
i do it like all yahoos.....on my fingers and toes.
EJ123
06-02-07, 09:41 AM
Porcupine
chrisvu05
06-02-07, 10:06 AM
on a calculator:rolleyes:
CdCf
06-02-07, 10:20 AM
Actually, I don't really do it either way.

314.159 becomes 300, from which I subtract 272, making 28. I then add 14 (300->314) to 28 and get 42.

Next, I subtract 828 from 1000 to get 172 and add 159. That's 331.

Answer is 42.331
Serendipper
06-02-07, 10:36 AM
I work right to left, adding remainders as I go.
atomship47
06-02-07, 10:38 AM
Porcupine

TREE!
jschen
06-02-07, 10:41 AM
Actually, I don't really do it either way.

314.159 becomes 300, from which I subtract 272, making 28. I then add 14 (300->314) to 28 and get 42.

Next, I subtract 828 from 1000 to get 172 and add 159. That's 331.

Answer is 42.331
I've heard of that method, but haven't gotten my mind around it except in simpler cases (in which case I do it all the time). Doesn't help that I basically never do mental subtraction nowadays.