Do we need to enter the fractional (decimal) amount for W2 related boxes on Form 1040 like box1,3,5? For example, $XX,XXX.YY, is the YY required to be entered?

If my W-2 address is incorrect, do I need a corrected one (does the IRS require?) from my employer or can I just enter the correct address on Form 1040 when filing my 2015 tax return?

Is it normal to only have a W-2 box 15 (for my state - Washington) without boxes 16-20?