Or maybe the question should be why are (Western) Arabic numerals (i.e., 1, 2, 3…) written from left to right?
My question is why is 125 written ١٢٥ and not ٥٢١
In: 38
There’s others with the historical (and correct) answer, but I have a slightly different additional (heh) view on the matter. In a way, numbers ***are*** written right to left. They’re just **read** left to right.
What do I mean? Think about how many people do basic arithmetic, like subtraction, long hand. (Better with a concrete example, so, two rng 3-digit numbers…813 and 729.)
`813`
`-729`
`—-`
You start on the right, don’t you? 3 – 9? Can’t do that, so borrow 1 from the left. 13 – 9 = 4. Ok.
**Write down** the 4
`813`
`-729`
`—-`
`4`
Then move left. 0 – 2? Also impossible, so borrow from the left again. 10 – 2 = 8. Write that down.
`813`
`-729`
`—-`
`84`
Moving on; 7 – 7 = 0. No borrowing there. And we ignore leading 0s.
So we have our answer of 84, read left to right, but written down right to left.
We do the same with addition and multiplication…long-hand division, not so much.
Now, I know this is not true of other mathematics. Many transcendental numbers like pi and e are notorious for not having a “right-most” (IE. final) digit. But then there’s numbers like Graham’s number, in which we *do* know the last digit (a 3), but do not know how long it is or what the first, or left-most, digit is.
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