When i am doing a mod question I do it like this:

Q: Find 144 mod 7?

A: 144 = 20 * 7 + 4

so

144 mod 7 = 4

But I cannot figure out 132 mod 257.

Q: Find 132 mod 257?

A: 132 = -1 * 257 + 389

so

132 mod 257 = 389 (This is what I am getting but it is wrong)

The answer is 132. Can anybody help me on what I am doing wrong on this particular problem?