Why is 'U' being removed from words?

I am always confused with colors and colours. I think in UK the correct spelling is colours, is "colors" how it is written in US?

I actually though that the u is added. When I was elementary, I was taught that color is spelled as color and not colour. Am I the only one who was aught this way? I grew up knowing that the spelling I used to this kind of words is correct, well no I doubt it. I'll research on this more.

American spelling differs in several respects from British spelling. The changes were due mostly to Webster's dictionary. You can see a summary of the differences and the history here: http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences

If you're using a standard American dictionary, it would spell the word color without the letter U. The UK and Australia and countries that had UK influence all spell it with a U. As to why they differ in spellings, I don't know. Check the history of the word. Probably there's a reason somewhere in the formation of the word.

There are some English words that have different spellings in American English and British English. Other words like center is spelled centre by British people.

Depending on where you come from. People from USA or countries colonized by USA removes U and Europe countries or countries colonized by European countries include U. It also depends on the curriculum that one uses.