To round 4.51 to the nearest whole number, follow these steps:
Identify the decimal part: In the number 4.51, the first digit after the decimal point is 5.
Apply rounding rules: Since the first digit after the decimal point (5) is greater than or equal to 5, you round the number up by 1.
Final rounded result: The number becomes 5.
Thus, 4.51 rounded to the nearest whole number is 5.