If John has completed 125 days of a 270-day fitness program, how many days does he have left?

To determine how many days John has left in his 270-day fitness program after completing 125 days, you need to subtract the number of completed days from the total days in the program.

Start with the total length of the program, which is 270 days. Then, subtract the days John has already completed, which is 125 days.

The calculation is as follows:

270 days (total) - 125 days (completed) = 145 days

Therefore, John has 145 days remaining in his fitness program. This aligns correctly with the selected answer, highlighting that by conducting a simple subtraction of the completed days from the total days, one can precisely determine the remaining duration.