Flash Cards: Heavy Division Shortcut

[RachelR514]

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 besides the first 18 in the numerator and the first 6 in the denominator. The flashcard has no explanation as to why this is okay, and I have never seen this before. Can you please explain? It's flashcard #6. Thank you!

[RonPurewal]

please post this query in the appropriate folder (= 'Manhattan non-CAT math').

thanks.

[RonPurewal]

although this may be enough for you to understand:

let's say a hotel room is $50 a night. then, for $4000 you could stay in that room for 80 days.

okay, now say the room is $51.74 a night. if you had $4116.24, you could stay in that room for ABOUT 80 days.
hopefully this is clear.

the 'about' is very important here. if you needed an exact solution then obviously this would not work.

if anything is still unclear here then please post in the appropriate folder. thanks.