that is the way i learned to abbreviate million.
MM = 1,000 x 1,000 = 1,000,000
but i'm an oldfag. they teach things differently now.
Roman numerals. M = 1,000. That's where it came from. there is no Roman numeral for million.
K for thousand comes from the metric system. K = Kilo = 1000.
and I went to school in a small town in rural Appalachia in the 1970's…before the Dept. of Education came in and fucked everything up.