Oh, dude, you're asking me to do math? Like, really? Fine, fine. 310 rounded to the nearest ten is 310. Because, you know, it's already a nice, round number. So, yeah, no need to change anything there.
When rounding 310 to the nearest ten, you look at the digit in the tens place, which is 1. Since 1 is less than 5, you round down. Therefore, 310 rounded to the nearest ten is 310.