What is 4 oranges + 5 mangoes?

I just got out of my computer system architecture class. Today's discussion revolved around floating point arithmetic. After seeing how computers actually go around floating point math, I couldn't help feeling "How the heck can that ever get me anywhere close to the real answer". The number of assumptions and simplification to the really complex problem of real number arithmetic makes it look impossible for computers. But well, I suppose we can live with the approximation. Currently, there are many sophisticated algorithms for carrying out the math (check the bc tool in linux). It seems as if we had the perfect tool for doing all the math we could think up of. Unfortunately, the world around us does not seem to follow the laws of arithmetic. For instances, what is 4 oranges + 5 mangoes? What is a collection of 4 random people called? Why not use the same word when referring to me and my brother collectively? Instead we are called siblings. There is a huge amount of symbolism in human communication. This symbolism is simply the random assignment of names to various things in the world. (If there is any logic to this assignment, I would love to know about it). This makes life very hard for us computer folks. Actually, it makes it very hard for us to instruct the computer system what it should do when someone tells it "please turn off." which is exactly same as "switch off." !

Can we ever conquer this army of symbols? The ever changing, contextual implication of combination of words, combined with background knowledge (which we can never guarantee if we ever have). I don't know. But it sure as hell would be useful, if we had programs which could crawl the web, look at this blog post's title and reply "9 Fruits".