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Finger counting

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M
317082.  Tue Apr 15, 2008 5:00 pm Reply with quote

Although most of us in the West look at counting on our fingers as something we'd shy away from once we were out of Junior School, don't dismiss it too hastily.
You can do more than count up to 10. How about 99, quite simply and without any weird, complicated maths or base numbers. I can't remember which country use this method, but I first heard about it on a Radio 4 programme a couple of years ago and have used it ever since.

How to count up to 99 with only 2 thumbs and 8 fingers:

a. Hold up your dominant hand (I'm left-handed) in a fist and start by raising only your index finger (1) -keep your thumb closed.
Index+middle (2), index+Middle+ring (3), index+middle+ring+little (4).

b. Now close all your fingers and hold up your thumb for 5.
Thumb+index (6), thumb+index+middle (7), thumb+index+middle+ring (8), thumb+index+middle+ring+little (9).

c. Now close your dominant hand to show a fist and also show your other hand with ONLY your index finger raised for 10.

Repeat a and b above whilst continuing to hold up your index finger on your non-dominant hand to count from 11 to 19. (so, 11 is both index fingers raised, etc.)

Follow c to show 20, but hold up your index finger+middle finger on your non dominant hand.

Follow this process of using your dominant hand to count the units and your other hand to count the tens until you get to 49 (All 4 fingers and thumb raised on your dominant hand and only your fingers raised on your non dominant hand.)
50 is similar to 5; close your dominant hand to a fist, close all the fingers on your non dominant hand and raise just your thumb: 50.

Carry on counting the units as before with the tens on the non dom hand being shown as thumb+index (60), thumb+index+middle (70), thumb+index+middle+ring (80) and thumb+index+middle+ring+little (90).

To coin an old TV show I used to love as a child, "...and that's HOW 99 fingers are the same as 10." (all digits on both hands raised.)

I'll try to find out the origins of this counting system and post anything I come up with.

Cheers.

 
Andrew
317104.  Tue Apr 15, 2008 5:35 pm Reply with quote

Wow that's very clever - I like it :-D

Yes, I've just been wiggling my fingers about counting from 0 to 99...

 
maiden
317110.  Tue Apr 15, 2008 5:40 pm Reply with quote

I usually use finger counting on a day to day basis ... I just thought I was a bit 'backward at coming forwards', cause math has never been my strong point (or just couldn't find a calculator - LOL), but it appears now finger counting is ok (the system I use is very similar)

:)

 
suze
317152.  Tue Apr 15, 2008 6:34 pm Reply with quote

Great system, M!

Though I'm really struggling with the 8; if I extend the middle three fingers, I can only keep the pinkie in by restraining it with the thumb. That's fine for doing the 3, but means I can't do the 8.

Have I got weird hands, or do others find it hard as well?

 
Sadurian Mike
317171.  Tue Apr 15, 2008 6:48 pm Reply with quote

I try but the hairs on my palms keep obscuring my fingers.

 
AndyMcH
317255.  Wed Apr 16, 2008 1:53 am Reply with quote

That's great... but I just have one question..

Why?

 
Ian Dunn
317256.  Wed Apr 16, 2008 1:56 am Reply with quote

If you used your toes, can you count up to 999?

 
Andrew
317257.  Wed Apr 16, 2008 1:56 am Reply with quote

I must say that I don't care 'why'...the point is that while people may well think that they can only count up to 10 with their fingers they can actually count up to 99....and I find that Quite (if not very) Interesting... :-D

 
Southpaw
317274.  Wed Apr 16, 2008 3:18 am Reply with quote

Very good. The most useful thing I can imagine it being for is long-distance number signalling, for example in the supermarket when your other half sends you to the other end of the aisle to tell her a price. Granted, it doesn't happen much, but it's good to be prepared.

I assume everyone knows the 3 times table helper? Hold up both hands with fingers outstretched and lower the appropriate finger for your multiplier, eg if you want to know what 3 times 9 is, lower your middle finger (thumb/1, index/2, middle/3).

Now count the digits 'before' the lowered finger (to the left of it if you're left-handed, right if not). These are your tens. Then count the remaining digits. These are your units. Thus lowering your middle finger yields 2 digits before, 20, and 7 digits after, 7, so 9x3=27. Obviously only works up to 9x10 but some of us need all the help we can get.

Does anyone else have a similar system for other numbers? My 7 times table is bad.

 
Lumpo31
317283.  Wed Apr 16, 2008 3:33 am Reply with quote

Southpaw wrote:
I assume everyone knows the 3 times table helper? Hold up both hands with fingers outstretched and lower the appropriate finger for your multiplier, eg if you want to know what 3 times 9 is, lower your middle finger (thumb/1, index/2, middle/3).
Very good, except that it's your 9 times table helper, surely?

 
AndyMcH
317299.  Wed Apr 16, 2008 3:48 am Reply with quote

Well the easy way for the 9 times table is :

subtract 1 from the number you're multiplying for your tens, subtract the number from 10 to get your units.


so for 7 times 9, the tens part is x-1, which is 6, and the units part is 10-x which is 3 - ie 63 !

Or you can get your tens in the same way and subtract that number from 9 for your units.

I dont know any other "easy" ways.. The weird thing is my brother taught me my 9 times table before I went to primary school - and also negative numbers...

 
M
317305.  Wed Apr 16, 2008 3:53 am Reply with quote

Quote:
why?


I believe the system was developed at a time when numbers didn't have written symbols, and was probably used by farmers who wouldn't have been able to read, write or produce written calculations. So, using your fingers to count to 99 is far better than having 99 pebbles in your shepherds pouch to count with.

I love the idea of distance communication of numbers, almost like a kind of Tick-Tack that bookies use. Although you'd have to be careful to keep your palms facing away from you when signalling to your partner at the other end of the Supermarket that you wanted 22 bottles of your favourite beer.

I'm still trying to get my brain around the 3 times table fingers. : )

 
ColinM
317324.  Wed Apr 16, 2008 4:06 am Reply with quote

If you could use your toes (which seems unlikely, given the degree of control you'd need over them) you'd get up to 9999. Though in any case I prefer the idea of using fingers as bits, so you can count up to 31 on one hand, 1023 on two, or 1048575 with both hands and both feet.

Still, the problem I find is that all of these clever tricks are far more complicated than just doing arithmetic in your head. Or on paper, if there's too much for that.

 
M
317341.  Wed Apr 16, 2008 4:31 am Reply with quote

Quote:
Still, the problem I find is that all of these clever tricks are far more complicated than just doing arithmetic in your head.


The point with the 99 finger count is that it's a system that was actually used rather than just a clever trick.

Quote:
...the point is that while people may well think that they can only count up to 10 with their fingers they can actually count up to 99....and I find that Quite (if not very) Interesting


That's exactly my point; in the West we are brought up to think that you can only count up to 10 with your fingers. In another part of the world a different method of finger counting was developed that enables a person to count up to 99. I think that's really Quite Interesting.

How I wish I'd known how to do that as a child learning numbers.

 
Southpaw
317364.  Wed Apr 16, 2008 5:02 am Reply with quote

Quote:
I'm still trying to get my brain around the 3 times table fingers. : )


D'oh, it's for your nine times table, not your three, sorry.

Just to re-iterate.

Example: 4x9

1. Hold out your hands, fingers outstretched.
2. Lower your left ring finger (4 fingers in, including the thumb, because we're multiplying by 4)
3. You now have 3 digits (thumb and 2 fingers) to the left of the lowered finger. 3 x 10 = 30.
4. You also have 6 digits to the right of the lowered finger; your left little finger and all the digits on your right hand. 6 digits = 6. 30 + 6 = 36. 4x9=36. Voila!

 

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