We might start by taking simple and obvious identity:

1 = 1

this implies 13 - 12 = 13 - 12

or 9 - 12 + 4 = 4 - 12 + 9

or 3^2 - 2*3*2 + 2^2 = 2^2 - 2*2*3 + 3^2

or (3-2)^2 = (2-3)^2

taking the square roots on the both sides, we have

3-2 = 2-3

Rearranging the terms we have

6 = 4

or 3 = 2

deducting 1 from each sides we have

2 = 1

Now multiplying both the sides by 4 we have

8 = 4 = 2 + 2

Q.E.D