Solve a puzzle

Solve this one:

x+4=12

What we want is an answer like "x = ...", but the +4 is in the way of that! We can cancel out the +4 with a −4 (because 4−4=0)

So, let us have a go at subtracting 5 from both sides:

x + 4−4 = 12 −4

A little arithmetic (4−4 = 0 and 12−4 = 8) becomes:x + 0 = 8

Which is just:x = 8

Solved!

(Quick Check: 8+4=12)