There was a post about Heavy Division Shortcuts a while ago, but it involved 10 ^ exponent, and this question does not. On one of the FDP flashcards, the question says: 1,863,471 / 626,502 = (estimate) a) 3 b) 4 c) 5 d) 30 e) 35 The answer says that you can basically cross out all the numbers beside...