Mymathlab!! trigonometry (pretty ez question). Rounding?

I'm supposed to round an answer six decimal places and the answer turned out as .5 so should i write .500000 or just .5??? i don't wanna get it wrong, it's for a quiz. and another one (where the answer is 90) is supposed to be rounded to three decimal places so should it be 90.000 or just 90. please help! the faster, the better. and preferably someone who knows for a fact