-snip-
mean 789.789 is value can u div pubkey by above value ?
Can`t and nobody can`t. devider must be integer not float. all pubkeys Q=k*G, where k - integer.
Sorry for continuing an off topic discussion, but:
Of course you can divide by 789.789 if you want.
because 789.789=789789/1000 , which doesn't have decimals in it AND you can divide and multiply by scalar numbers.
Don't know why would anyone want to divide by 789.789, but it s possible