What is the quickest way for you to count to 20 using only the fingers of your hands?

[kaleidoscope]

I'm trying to find the most intuitive way to count to 20 using only the fingers of your hands. Right now my favorite is using 4 fingers on one hand to count groups of 5 from the other. Any other ideas? Please participate!

 

[pwsnafu]

I don't know if this counts but I was taught

1. Left thumb raised
2. Left thumb and left index finger raised
3. Left thumb, index and middle
4. Left thumb, index, middle, ring
5. All fingers (and thumb) of the left hand
6. All except thumb
7. Middle, ring, little fingers
8. Ring and little finger raised
9. Only little finger raised

This gives 0~9 on one hand. So the other hand counts the tens column.
Come to think about it, it seems having the ones column on right hand is probably more intuitive.

 

[Exocet]

I have a way of counting to 99 on both hands, might be a bit tricky to write out but I'll give it my best shot!
Count to 4 on your right hand using only your fingers, then hold out the thumb on its own for 5, and count up to 9 with the fingers til we have the whole hand out.
Now we can add 1 finger on the left hand for 10. If we start again and repeat the process on the right hand then we can add 20 to the left hand and 30 etc. up to 99

 

[Mensanator]

I don't know if this counts but I was taught

1. Left thumb raised
2. Left thumb and left index finger raised
3. Left thumb, index and middle
4. Left thumb, index, middle, ring
5. All fingers (and thumb) of the left hand
6. All except thumb
7. Middle, ring, little fingers
8. Ring and little finger raised
9. Only little finger raised

This gives 0~9 on one hand. So the other hand counts the tens column.
Come to think about it, it seems having the ones column on right hand is probably more intuitive.

Just count in binary. You can get to31 on just one hand.

 

[TwilightTulip]

Just count in binary. You can get to31 on just one hand.

I'd be weary of doing this in class. Especially with 100 and 101

 

[willem2]

Just count in binary. You can get to31 on just one hand.

We want the quickest way, so we should use a gray code, so you only have to move one finger at the time.

 

[camillio]

Just count in binary. You can get to31 on just one hand.

Sounds like 2^10 masterclass :D

 

[dodo]

... touching your teeth?
... pointing at a calendar?

Now seriously, I saw something in a documentary (only 30 seconds on this link need to be watched):
http://www.youtube.com/watch?v=6CHrIqeENYE&t=24m59s

 

[disregardthat]

I can count to 120 on one hand.

5! = 120, just take the order into consideration.

 

[Frogeyedpeas]

@disregarthat what a wonderful combinatorics joke ;)

 

[Ynaught?]

I like this way... Starting from left to right with palms down, the tip of the left pinky is 1. Counting through the fingers, the tip of the right pinky is 10. The top knuckle of the left pinky is 11 and so forth. Going though the knuckles, you get to forty (I count the thumb joints at the base of the palm as 35 and 36). 41- 50 are no tips and no knuckles on each hand.

 

[BobG]

I have a way of counting to 99 on both hands, might be a bit tricky to write out but I'll give it my best shot!
Count to 4 on your right hand using only your fingers, then hold out the thumb on its own for 5, and count up to 9 with the fingers til we have the whole hand out.
Now we can add 1 finger on the left hand for 10. If we start again and repeat the process on the right hand then we can add 20 to the left hand and 30 etc. up to 99

http://www.cs.iupui.edu/~aharris/chis/chis.html. This is the best way of counting on your fingers (especially if you have a small crew and have to count how many people have evacuated, all while holding a checklist in one hand).

Just count in binary. You can get to31 on just one hand.

This works well. If you extend this to counting on all of your fingers and toes, you can count for almost two weeks!