37
submitted 1 month ago by cm0002@lemmy.cafe to c/til@lemmy.ca

YSK You can count past 1,000 on your fingers by using binary, instead of just 10

With just one hand, you can count to 31, and with both hands you can reach a whopping 1,023. This is because the placement of the held up fingers matters, rather than the amount.

It can be very useful in everyday use, being able to count to huge numbers when you don't have your phone or pen and paper nearby.

top 16 comments
sorted by: hot top controversial new old
[-] Multiplexer@discuss.tchncs.de 11 points 1 month ago

You can even count to 59k using ternary, introducing a third, half-raised, finger position.

[-] lvxferre@mander.xyz 8 points 1 month ago* (last edited 1 month ago)

This is cute but not practical.

Memorising all 2^n for 0≥n≥10 (1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024) is reasonable, but you'll need to add a lot of them at the same time to convert the counting in your hands to a base 10 number (that'll use elsewhere). Stuff like 256+128+64+8+2+1; it isn't difficult but laborious, you know?

Plus the gestures can be sometimes awkward, depending on how flexible your hand is. For example, at least for me it's a bit tricky to lift the ring finger up without either the middle or the pink.

I have a different strategy to count large numbers by hand. It's up to 12 with one hand, 144 with both. But it feels comfortable, and rather intuitive:

Put the tip of your thumb on the indicated places to count 1, 2, 3... 12. With one hand; if you want to count past 12, use the other hand to count dozens (12, 24, 36... 144).

Provided you memorised the multiplication table for 12, for any given number you'll perform at most a single addition, like 84+7 or similar.

(I have a suspicion the Sumerians counted this way with one hand, and one finger per dozen with the other. That's why a lot of their units 5*12=60 as a basis.)

[-] hesh@quokk.au 5 points 1 month ago
[-] PeriodicallyPedantic@lemmy.ca 3 points 1 month ago

I like your way, learning as an adult.

But if you were to hypothetically teach a child, then binary would be easier, and they eventually would memorize the positions.

Although realistically by the time they need their second hand, they probably don't need to be counting on their fingers anymore. And I don't think either of these systems is especially helpful for higher math, unless you're multiplying or dividing by a power of 2. Maybe? I forget my 2s compliment operations now.

[-] BCsven@lemmy.ca 2 points 1 month ago

I have the gene where my second thumb joint/knuckle near the base doesn't bend. I can only count to 10 using this method. 11 and 12 are not really reachable. Even 9 is a bit of a stretch.

[-] lvxferre@mander.xyz 2 points 1 month ago

Worst hypothesis, even if counting just to 8, you're still using a single hand, so it's an improvement over counting to 5 with fingers. Couple it with the other hand and you're counting up to 64.

There's also the Chisanbop method @hesh@quokk.au mentioned, for that your unbending joint shouldn't be an issue, and it allows you to count to 9 with a single hand (99 with both).

[-] jaselle@lemmy.ca 6 points 1 month ago
[-] Multiplexer@discuss.tchncs.de 4 points 1 month ago

Sometimes its harder to not try 132.

[-] BCsven@lemmy.ca 4 points 1 month ago

Sure , this is neat, but counting single digits on digits is easy for people.

Mentally adding 16 to 8 and 4 is where people will find this more complex, especially if you have easy stuff like 7+5, you have to do the math in your head to move it from 4,2,1+ 4,1 to 8,4.

[-] Corkyskog@sh.itjust.works 4 points 1 month ago

11 is extremely hard for me.

[-] funkless_eck@sh.itjust.works 2 points 1 month ago

pianist here : it shares a tendon with the pinkie so your best bet is to bend at the first finger joint (as opposed to the knuckle) or extend it parallel to the palm at a right angle rather than straight up from it

[-] Multiplexer@discuss.tchncs.de 1 points 1 month ago

For me basically anything where the ring finger has to act independent from the others is a little bit hard, but still doable.
(11 is one of those numbers)

[-] Rentlar@lemmy.ca 1 points 1 month ago

Try 717, (or just 13 in your right hand)

[-] Multiplexer@discuss.tchncs.de 2 points 1 month ago

So ring finger, middle finger and thumb raised?

Is this some hand sign with special meaning I should be aware of?

[-] Rentlar@lemmy.ca 1 points 1 month ago

Not any particular meaning, it's just a tough position to hold with my hand

[-] fascicle@leminal.space 1 points 1 month ago

This reminds me of an engineer ever walking me through a bringup test of a board and telling me to flip some dipswitches so that it added up to some binary number and I just stared at him like can't you just tell me which dips to flip

this post was submitted on 17 Jan 2026
37 points (93.0% liked)

Today I Learned (TIL)

8840 readers
1 users here now

You learn something new every day; what did you learn today?

/c/til is a community for any true knowledge that you would like to share, regardless of topic or of source.

Share your knowledge and experience!

Rules

founded 3 years ago
MODERATORS