I find it hilarious that so many people are so worked up on the rounding on the third significant figure of a number in the comments section of an article about "back of the envelope estimation hacks".

I did this exact calculation and it comes out to 730, exactly like GP said.

Since you're getting downvotes and several others have posted disagreeing, I'm posting to agree with 730.5. I also get 365.25 * 2 = 730.5. I have no idea why other people are saying this somehow comes out to exactly 730.

> Technically it is 731 if you round up.

Actually, since 365.25 is a bit high (if it were exact we would all still be on the Julian calendar), I would round down to 730 since the multiplication gives a little less than 730.5. But that's still not the same as saying the multiplication gives exactly 730, as others are saying.

No, that evaluates to 730. It's the same as 365*2=730.

Other useful numbers:

Days in a year: 365.2425 (exactly, under Gregorian calendar)

Days in a month: 30.44 (approximation, a twelveth of the above)

365 * 2 = 730 :)