Modulo

>>59615322
What's the issue here?

>>59615322
https://www.khanacademy.org/computing/computer-science/cryptography/modarithmetic/a/what-is-modular-arithmetic

>>59615555
think of it like the remainder in a division problem, very simple

12 % 15 is the same as saying "What is the remainder of 12 divided by 15?"

>>59616180
why "think of it like" when it literally is division with remainder?

modular arithmetic preserves + and *

what that means is that
27 is congruent to 12(mod 15)
27 mod 15 = -3 mod 15
so then you can determine 27^17 mod 15 because 27 = 3 in Z_15

>>59616237
27 = -3 in Z_15 sorry