How do I round percentage 15.894 percent to two decimal places?

If the 3rd digit is 5 or less, you simply discard it.

If the 3rd digit is 6 or higher, you raise the 2nd digit by one, and discard the 3rd.

(if the 2nd digit is 9, it becomes 0 and the first digit raises by one.)

15.894 rounded to nearest hundredth = 15.89 (rounding down)

15.897 rounded to nearest hundredth = 15.90 (rounding up)