Hi there.

I've looked over my notes for my last lecture only to realise I don't understand what's going on with them at all and would like to know if anyone else can explain how the following works:

in $\displaystyle \mathbb{Z}$/11:

8+7 = 10 mod 11

We all know that 8+7 does not equal 10 mod 11, so what's going on?

It then goes on to prove that

7+8 = ?

7+8 = 15, too big so /11, remainder 4

7+8 = 4 mod 11