Question

how is 2+2=5

Answer 1

If you combine the two's together.

Answer 2

then it equals 4

Answer 3

with the thought pressure

Answer 4

5 is actually a valid engineering solution to the expression 2+2.
If you measure the length of something very small, lets say '2mm', then we have to realize that in truth, that object could measure up to 2.49mm. If this was the case then the 'error' on our measurement is 0.49mm. Also, the smallest error that we can have is zero. That would mean the object we measured was exactly 2.00mm.
Now say we took the measurement of two objects both of length 2mm. The sum of both lengths is technically 4, but if we wanted to construct another object to place those two objects in, then we need to account for the error in our measurements of the objects. The largest possible length of the two objects is 2.49+2.49 which equals to 4.98 which is ~5.
Thus in an engineering calculation, we would write 2+2=4 (+ or - 1).

To summarize, 2+2=5, for very big measurements of 2. :)