[quote=Ghosty]“If two and two added up to four, and another number also, what would that other number be?”
If you’re talking strictly mathematics on the real number line, using either perfect precision real numbers or maybe restricted to integers, addition as normally defined, etc. etc. then yes, two and two added up to four. This is only theoretical though.
In real life, two plus two often don’t add up to four. For example, depending on what units I choose and what physical realm, I can pretty much get 2+2 to add up to all sorts of things. That’s because the Real World doesn’t obey our rules of mathematics. Our rules of mathematics are made for us to estimate and model the “real world.”
The “real world” is not so cooperative, but we like to pretend it is and often it is close enough that we’re not Late For Dinner so even though our “truths” are actually relative we can consider them absolute for most intents and purposes.
Unless you’re an engineer. Then you have to have a better understanding of how things really are, or your stuff won’t always work. Math is nice and neat, and if you’re only adding apples and oranges it usually works As Advertised close enough to figure the amount you have to pay for them.
Here’s a physics quiz for you, simpler than many homework problems I faced decades ago. I will turn it backwards and tell you how the math works out, and you tell me what the problem was about, and what the units of measurement are. (This is not hypothetical or a trick question; this is a mathematical representation of the Absolute Truth, or at least a whole lot closer to it than 2 + 2 = 4 in this situation.) All quantities are in the same units of measurement:
2 + 2 = 2.77