Tom, you would do well to listen to yourself. Do some reading and use this as opportunity to learn about how math relates to the real world.
Peano's work specifically proves that 2+2=4 whenever the successor function, i.e. counting, works. Macario's example of the water and alcohol solution is on point: Volume of a liquid is not strictly countable, being subject to constantly changing physical states of pressure and temperature, so 2ml + 2ml is not something that makes sense. Atomic nuclei are, generally, countable, as nuclear reactions can be ignored in many cases. In this case, 2g + 2g does make sense, strictly because what you are adding is countable. Indeed, that the math doesn't make sense for mixing liquids or stacking sponges is a clue that there's more going on! A chance to dig deeper and learn something... an opportunity a thinker like you must cherish.
If you have a situation where counting does not apply, it follows that 2+2 if the uncountable may not result in 4. Oh shit, better claim that math is broken? See the absurdities in this thread like, throwing this out there, eyebrow + stoicism = Pixar. The symbols + and = don't mean the same thing here as they do in 2+2=4. When semiotics and symbolic reasoning come in, formal logic and math take a seat. Pineapple + pepperoni = tasty pizza is not math, but I can use the symbols to communicate anyway. If you attempt an inversion, and find that 2 pineapple deliciousness + 2 pepperoni deliciousness = 3.78 pizza deliciousness... take it as opportunity to learn.