我如何用NSNumberFormatter对数字进行循环?

I've got a calculation for example 57 / 30 so the solution will be 1,766666667.. How do i first of all get the 1,766666667 i only get 1 or 1.00 and then how do i round the solution (to be 2)?I've got a calculation for example 57 / 30 so t