the answer is 3. the number before the decimal is the whole number. if the number after the decimal is smaller than 4, round down and if the number after the decimal is greater than 5 then round up.

BettieZumbrunnen

You look at 3.1 and you say to yourself . . .
"Self ! Look at that number. The next bigger whole number is 4, and
the next smaller whole number is 3. Which one is nearer to 3.1 ?
Did you say 3 is ? I'm so proud of you !"