I am reading a book about Reimann in which Field theory is introduced.
I undertand the calculation of a clock arithmetic but I am struggling to understand the calculations for addition and multiplication of a proper field with 4 elements. (Power of a prime).
Why is 1+3=2, in the clock arithmetic it is zero which I understand.
Why is 3+3=0, in the clock it's 2 which makes sense.
The multiplication table is equally confusing.