The rounding on my calculator is often different than what is rounded on the answer choices. How many decimal places are we supposed to use on our calculators? I am using 4 at the moment.
I always used 4. But one of my students once pointed out (rather intelligently) that using 4 decimals means that you are effectivly using 2 decimals when expressing percentages in decimals. I still (rather stubbornly) work with 4, but it really doesn't make a material difference.