In Plurals^x, Contractions^x, Dates^x

Grandmother's making me a new blue blanket. Can you tell me about the " 's " in Grandmother's? I'm confused about the use of the apostrophy. From the www.Dr.Grammar.org The apostrophe is used for three purposes: to indicate the omission of one or more letters (can't, don't) or figures...

If this is for the US, don't use "condominia." Apparently it is a word, but I have NEVER heard it before. Much as I don't usually use Google to validate, there are 21.5 million hits for condominiums, and 13.5 thousand for condominia. You don't need the "or not" in the sentence. Arvsworld, just...