An alternative way to see subtraction using addition

This only works with 5.

So it only works if the 1st number is 1?

Been doing this since 3rd grade cuz I found regular subtraction harder lol

If it works so well, how come he couldn't get the last one?

Apparently, only if you subtract by 5

Saved !

My mind is usually pretty quick with calculations, but it doesn't work that way. I suppose this is only possible because 5 is the midpoint of the ten-digit range, 10. If the range were 20 instead, the same operation would only work with 10.

genius

Not true for most subtractions... 🙄

Modern computers subtract by adding the two's complement of the second number and discarding any leftover bit on the left, just as John von Neumann proposed in 1945.

But doe NOT seem to work 100%... How about 15-7=

lol Only works when you’re subtracting 5

12

12 - 7 = 19

Can you not simply math?

12

中間値でしか成り立たない 16進数なら8 何の意味があるのか

12

12 square root 1

20-5=?

지랄 노

12-2でも同じことやってみてくれ😅

Alternative?? Been doing only this since forever . What’s the other way ??