Download and run this java calculator, it's very slow and heavy but it's good for manual calculations which is why you can only do manual calc with it.
https://github.com/MrMaxweII/Secp256k1-Calculator
Select scalar on both sides, and place private keys in hex format, then select * , + , - , ÷ , and see for yourself what would be the result.
What you should consider when dividing an odd key, dividing any odd key by 2 will always give you .5 ( point 5, half ), anything on the left side of the point . Is your actuall result no matter if you are dividing by 2 or any other number, but for example we use 2, and anything on the right side of the point . Is a 2^255 + key, we don't want that, so we subtract that from our result to get the actual answer.
3 divided by 2 = 1.>5 < this 5 here means half of n, so if we subtract it from 1.5, we will get 1, our actual result.
Now lets make it a bit difficult, let us divide 7 by 3 = 2.33333333333333333333333333333333333333333333333333333333333333333333333333333 3333333333333333333333333333333333333333333333333333333333333333333333333333333 3333333333333333333333333333333333333333333
Now to get the n/33333........... more 333333..... etc, no need to do any complicated calculation, we just divide 7 by 3 mod n to quickly get the result, then we subtract it from the result to get our key.
Never mind all the above, I have something to twist your minds, take the following key and double, divide, do many other things with it to get really confused about how EC works. 😂
Introducing to you 2^256 of secp256k1
Try multiplying it by 2, 3, 4, 5 etc as well as dividing it, this little sucker is hiding it's half under the ground!
Thanks for the info bro. I use this calculator, it works great! And how do we subtract half of n from the point X and Y coordinates?, or do we need to get the coordinates x, y from half of n? (if there is, then what are the coordinates of half of n). Or was the subtraction just an example to show so that I would understand?.
OK, tomorrow I'll try to test this key))