Dividing public keys is not the same as subtracting, actually if you don't know what you are doing, you'd end up in 2**255 + ranges, for instance if you divide the public key of 11 or 0xb by 2, you'd end up with n/2+5. Or 5.5 and that would be half of 1(n) +5. Whatever number you are dividing, if it's odd and if you are dividing by 2, 3, 4 up to 9, you can get the correct result, here is how:

13/3 = 4.33
1/3 = 0.33
0.33 - 4.33 = 4

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What you are asking is simple math really, in order to reach 1 from 22, you will have to subtract 1, 21 times from 22.

The thing is, what are you trying to do exactly? If we know what the goal is, it'd be easier to assist. 😉