How do you calculate the number of intervals needed to cover a target with the M224 or M252?

To determine the number of intervals needed to cover a target effectively with the M224 or M252 mortar systems, calculating the number of rounds to be fired minus one is appropriate. This method is based on the understanding that each round creates a specific segment of coverage, and by subtracting one from the total number of rounds, you account for the fact that the first round does not need an additional interval before it can be released.

In practical terms, when engaging a target, the first round is considered to establish the initial impact point, with subsequent rounds contributing to a spread across the target area. Therefore, the intervals are based on how you distribute fire so that the total rounds fired can cover the intended area effectively, with the planned intervals accounting for coverage overlap and dispersion factors.

The other options do not accurately reflect the necessary calculation to ensure adequate target coverage based on standard practices in mortar operations. For instance, dividing the number of rounds by two or multiplying by three can lead to incorrect intervals, while adding a round would underrepresent the efficiency of the first round already establishing coverage. Hence, subtracting one from the total rounds to be fired accurately reflects the tactical approach needed for effective mortar engagement.