So, \(3.168\) rounds up to \(3.17\) (to two decimal places). Round \(17.839\) to one decimal place. If the number at the next decimal place is smaller than five then leave the previous decimal ...

\(3.168\) is correct to three decimal places as there are three digits after the decimal point. If the number at the next decimal place is five or more add 1 to the previous decimal place ...