16 rounded to the nearest ten is 20. When rounding to the nearest ten, we round the number up to the nearest ten if the last digit in the number is 5, 6, 7, 8, or 9. We round the number down to the nearest ten if the last digit in the number is 0, 1, 2, 3, or 4. Since the last digit in 16 is 6, we round up to the nearest ten, which is 20.