To round 12.1 to the nearest whole number, follow these steps:
Identify the decimal part: In the number 12.1, the first digit after the decimal point is 1.
Apply rounding rules: Since the first digit after the decimal point (1) is less than 5, you keep the number unchanged.
Final rounded result: The number remains the same 12.
Thus, 12.1 rounded to the nearest whole number is 12.