



 
Hi Larry, I have not seen MM as an abbreviation for million but I did find a reference to it in Wikipedia. M is the Roman numeral for 1,000 but in the metric system M designates the prefix mega which is a million. For example MW is a megawatt. On the other hand m designates milli or one thousandth so mm is a millimetre or 0.001 metres. To minimize confusion I would stick with K for a thousand. K comes form the Greek kilo which means a thousand. In the metric system lower case k designates kilo as in kg for kilogram, a thousand grams. Even here there is some ambiguity. In the language of computer science K is 2^{10} = 1024. Penny  


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