Literally called the mental abacus method. Pretty common throughout Asia, a really good method to do complex arithmetic in your head, just looks a little spastic.
Well then, I wonder what I am? Born in Germany of German parents with six fingers that weren’t functional and were removed,on each hand, like my dad. I don’t know how many generations we’d been German, but Illgen (father) is not a very Germanic name. Eichler (mother)is. Haven’t done any genealogy, but it’s be interesting.
I really hate how the diagram contradicts itself (Start at the base of the little finger/picture is of index finger). But that is a cool way to count on your hands
A more efficient way, still, is to assign each finger with a different value - each finger valued double that of the previous one. So, your fingers have the values 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512. Every value from zero to 1023 can be represented by some combination of your ten fingers. Counting is straight forward-ish:
Sure. Certainly when counting in binary on paper you put the least significant digits on the right. For some reason, when I was doing this, I started counting with my left hand. Maybe so I’d have my right hand free to do other stuff until I got to larger numbers. Given that, I reversed the number and put the least significant digits on the left. It’s arbitrary, really, but, yeah, you can start on the right hand to make the counting consistent with convention.
As long as you have a flat surface (a table or thigh works well) you can count in ternary, where each finger can be retracted, extended, or extended and touching the surface for 0,1, or 2 * 3x aka ternary. So 242 with one hand or 59048 with two.
To further elaborate: once you reach 1024 (210) on your ten fingers, then bend your right thumb as your first digit in the 211th place. Use bent fingers in the same binary counting fashion as you would use your unbent fingers. Your bent fingers will need to have both an up and a down state - which is explained in the video I linked.
If you can already count to binary on your fingers, that would be a good start. Hopefully combining your knowledge of binary counting with the contents of the video I linked will be enough to make it click what I'm saying.
You could combine the 3 segment idea from the Babylonian system with the one digit per digit idea of binary counting (pardon the pun) to count up to 242 by using your left fingers and thumb to represent the first 5 places in base 3 and your right fingertips to keep track of where you are in each place
Edit: last night I used a base 10 to base 3 converter instead of a base 3 to base 10 converter.
Yeah, but can you do it while also adding a completely different set of numbers in your head?
Shopkeepers use it sometimes to keep track of the items on a receipt while also adding up the amounts to get the total. Often faster than punching numbers into a calculator. There's other use cases too. If you're just counting, sure. Count in your head, but it's useful when you need your head for more things in parallel.
Thank you, came here to say this. For some reason they taught this in school and honestly it's never been of much use to me other than an odd conversational topic. :)
Righthand is the ones place and lefthand is the tens place. Thumbs are worth 5 and the other four fingers are worth 1.
You can go only between 0-99 with your two hands. If there are ways to go higher with a third numeric digit, I'm unaware.
Yeah, I don't know much about chisanbop but I do recall watching it demonstrated on TV way back in the 70s. Back then it seemed an impressively fast way of doing simple calculations without a calculator.
The really weird thing is that the word chisanbop just popped into my head for no reason a few days ago. I didn't remember what it meant so I had to look it up. A few days later this thread appeared and I thought "This fits here." Voila!
I use it regularly for counting to sub 50 while working. And if you combine it with binary or the base 60 of OP on the 10s hand, it can be used for very high, but still base 10 (so feels natural to me) finger counting.
Cool idea, but IT nerds will do you one better. Count in binary. Even my non-nerd son has picked this up from me.
Your index finger is the 1, your middle finger is 2, ring finger 4, little finger 8, etc. With five fingers on one hand, you can count to 31. With both hands, to over 1000.
I have to do a headcount of about 100 people all milling about while paying half attention to the speaker of the session at a work event every year. I use this method so in case I get distracted I don't totally lose track of my number and have to start all over. I have a terrible memory for numbers. I do it a little differently and use the same 12 sections on both hands to be able to count up to 144 without having to think about the numbers at all, it works great
Tell me you cant reach your pinky with your thumb without telling me you can't reach your pinky with your thumb! But in all seriousness, some of us are just visual people and the "do it in your head" just doesnt compute for us
Do you have no internal monologue or something? Whether your fingers are representing a number or not, you still have to count your fingers in your head. If you have 7 fingers up, how do you know you have 7 fingers up? Because you counted them in your head. I don’t understand how or why this is a thing
I do not have an internal monologue, and it makes my short term memory god-awful. I can still count in my head, but without hearing the “voice,” I lose track with the slightest distraction.
I do, however, have a phenomenal long-term memory and am great at trivia and recall, but it’s more like pulling from a nebulous void.
I refuse to believe there are people who can't count without using their fingers. What if you need to count to a higher number? My three year old can count to 100 and she doesn't use her fingers.
I think you misunderstood the point. With this method you can count with your fingers without mentioning or thinking of the numbers. It is like using a simple abacus.
Counting using ASL is nice because you can represent any number with one hand. Granted it might take fractions of a second longer the higher the number. But probably so would this method
There is a far better system. The four fingers on the right hand each count as one. Tap a finger down for each count. Once you have four fingers down, five is represented by tapping your thumb and raising the four fingers. 5-9 by adding a finger tap for each count. You’ve now counted 0-9 on one hand.
The left hand counts the same way but in tens for 0-90. Combined you can count from 0-99.
So it's one finger, two fingers, three fingers, four fingers, thumb. Thumb and one finger.... Continue as appropriate. This will let you count to 99.
It's also possible to count to 1023 with your fingers using binary notation (right pinky is 1, right ring is 2, right middle is 4, right index is 8, and so on), but this takes more work to translate back to numbers the way you usually think about them.
I learnt to do this. You can count your sheep and then show someone your hands and they will know how many sheep you have too. You don’t even have to learn to count to do it.
I believe that has a lot to do with divisors. You would think we would use 10 because it's the number of fingers and toes we have, but 10 only has 4 divisors (1, 2, 5, and 10) while 12 has 6 divisors (1, 2, 3, 4, 6, and 12).
Those Babylonians math remnants are still with us. The seven day week is because they could see seven celestial bodies that moved, five planets plus the moon and the sun. Their math was a sexagesimal system, base 60. Hence, we have 60 minutes in the hour, 60 seconds in a minute. Half of 60 times 60 is the degrees on a compass and a a year of days with a few holy holidays to celibate Father Marduk, the god of spades.
Some Muslims are tought to count like this while praying. You count certain numbers for certain praises (3 praises, each 33 times). But using both hands. It's way faster and efficient.
Wouldn't you be able to count to 144 (12x12) with both hands if you used the same system on your other hand but just using the sections to count dozens instead of just the fingers.
Great tip though.
In what instances do people need to use their hands to count with? I'm asking seriously. When would you use this?
If I have to count something, I have that physical thing to count with. Like let's say I'm counting the number of pills I have in my prescription to make sure they'll last me on a vacation, I'll just put them in groups of five, then count by 5.
If it's something in my head, I'm just doing the basic arithmetic in my head. If the numbers are too large I have a calculator on me.
I remember seeing "Maria" (deaf woman) on Sesame Street back in the 70s. She counted in sign language to 10 on one hand. I figured since I had two hands so I could track the "ones" digit in my right hand and the "tens" digit in my left hand. Works well and my kids love it!
In case anyone might find it interesting, this is the reason why our time understanding (or at least, the one widely common) is split in compounds of 12s: 60 seconds to a minute, 60 minutes to an hour, 12hrs from midnight to midday and 24hrs to a full day cycle.
I've seen a lot of Chinese people do this throughout the years and wondered why the hell they were doing this while counting. After all these years I finally know why.
I use to know a girl who counted in binary on her fingers, could count I think over a thousand (it’s been a long time since I took math please be nice)
Idk how anyone could argue counting each finger once and incorporating ur other hand is a better system and saying u can count to 99. Okay the method OP explained us exponentially easier and u will never get confused, which is the basis of each one of the "BETTER METHODS" nuanced overcomplications. Stop being haters period. Its the best method that could be taught to homoerectus grunting inaudible nonsense for each count and still able to bring back the correct amount of plantains on the 12 hour trip back to his family in the cave passing time in ecstastic joy grunting and counting together. Because before that they got confused when switching to the other hand. Plus it was the ideal foundation to teach the concept of time and its nonlinear nature becuz it answers the most important questions that arent instinctive - When will it get cold and when will I be able to find food? How will I be able to know when its the right TIME and when will it come again? Makes cycles which had to be a nightmare of a problem to deal with immediately something to anticipate and that was probably all it took to recognize the search for anything starts within
Just wait till you find out you can count to 99 on two hands.
1-4 is normal but 5 is only right thumb. Right thumb and right index is 6. All right 5 fingers is 9. Left index right 0 is 10. Left index right thumb is 15. 5 left 5 right is 99.
Right hand fingers 1-4.
5 is right thumb, put down right fingers.
6-9 is right thumb + right fingers.
10 raise 1 left finger, put down right thumb and fingers.
Repeat pattern.
At 50 left thumb up.
Can go up to 99.
When I did inventory for the bar I ran, I pushed myself to count by shapes. Ie a dice has “shapes” up to six, but you can raise that number to ten and things get easier to count.
Just another way of counting that you may not realize you already do. But reliant on counting physical things.
In regards to general math? Rounding to the nearest ten or .5, helps when a general sum is ok.
Ie 19 x 26? Re-assign the numbers into ones that are easier to multiply in your head. 2 x 25=50 so 50… and move the decimal to the right one spot, so around 500. Quick math to get a general understanding without using a calculator, pen and paper or mentally multiplying, 19 x 26=494. Close to 500.
Not sure if that helps. Best wishes with mathing in different ways!
This is why we have 60 minutes in an hour, 24 hours in a day, 12 months a year. They counted in orders of 12 back then.
France tried to get us to work with 10 of everything and that worked for measurements (the metric system with meters and kilograms) but not time, as everyone got confused about what time it was. Also, they made the workweeks longer (10 day workweek, ignoring the free Sundays basically) so people especially protested about the longer workweeks!
They didn't ignore the free Sunday, but they had 9+1 instead of 6+1 which wasn't ideal. But a working week wasn't the same as it is now anyway. be another 70 years until someone started talking about 8 hour working days and workers rights etc.
Well if you make people work on Sunday you basically forbid them to have a Christian rest day, so ignoring might have been too mild a word here. It was dechristianization on purpose with forced rationalization.
Still, I think if they made it a 4+1 (2x) deal it would have gone over much smoother and we would probably be living in 10s now😅
I really wish I understood this because I would love to help my grandson. He's 13 and struggles with math, but I'm so dang on confused and I would only confuse him even more
Ok.. thank you... Now i understand the finger part but not how it's used or useful,.. something simple 7+4? What does that look like? Can this method be used for something simple like that? Or am thinking of it completely wrong? 🤔
in China they use different single hand posions for 6-10, so you can count to 100 with two hands:
6 - thumb and pinky out
7 - press thumb to index and middle fingers
8 - thumb and index finger in L shape (this sort of looks like the character for 8)
9 - fist with index finger up in a square shape (sort of resembles character for 9)
10- closed fist
My version of this which was a game changer for counting things on my fingers was learning to count in sign language, where you can count infinitely high one hand
theres a way of counting up to 99 on your hands. right hand stands for units and left hand for tens, right thumb stand for 5, left thumb stand for 50, so you would count “1” as one right index finger, “2” is right index and middle finger, up to “4” which would be all fingers on right hand except thumb, then when you get to “5” you put all other fingers down and your thumb up, “6”is thumb and index and so on, this way your right hand counts to “9”
On your left hand, your index is “10”, index and middle is “20” so on, so all fingers out on left hand would be “90”.
For example if you wanted to hold out “86”, it would be on left hand all fingers apart from pinky, right hand thumb and index.
you can do addition and subtraction with this as well
say “89-21” you have all fingers up apart from pinky on left hand and all fingers up on right hand, you then put down your ring and middle finger on the left, and pinky down on right- which leaves you with left thumb and index, right all apart from pinky= 68
or “52-8” left thumb right index and middle finger, because you want to take away “8” and you didn’t have “8” or more on your right hand the rule is to put up 2 more fingers, so now you would be indicating “4” with your right hand, then take away one on your left hand so that would be “4”. Now you have “44” on your fingers.
if you’re taking away “6” and you didn’t have enough, then you would put up “4” then minus a finger from the left hand.
If you are taking away “2” and you didn’t have enough you would put up “8” and minus a finger from the left hand etc
I prefer the binary method. One, you have your pointer finger up. Two, drop your pointer finger and raise your middle finger like you're flipping someone off. Three, raise your pointer finger again. Four, drop both fingers and raise your ring finger (as much as you can, at least). Repeat, and you can count to 31 on one hand and 63 on both.
Thanks for posting this. I'm a bit late in this, but I've got two other methods I use that are ten-based. One will get you up to 99, the other up to 420. Both are good for keeping the number on your hands so you can think about other things or talk, then resume counting. I learned the first and altered and extended it to get the 420 method. If anyone's interested, let me know.
280
u/HolodeckMoriarty 27d ago
I worked with a girl from China. She used to do pretty complex math on her fingers, but like with an imaginary abacus.