In calculating a DEA number, what mathematical operation follows after adding the 2nd, 4th, and 6th digits?

To determine the next step after adding the 2nd, 4th, and 6th digits of a DEA number, the procedure involves basic arithmetic to ensure the validation of that DEA number follows specific regulations. After obtaining the sum of the 2nd, 4th, and 6th digits, you then move on to the next stage in the calculation, which is to take that sum and add it to the sum of the odd-positioned digits (the 1st, 3rd, and 5th digits).

This step is crucial for confirming the legitimacy of the DEA number as it evaluates the entire structure according to the DEA's formatting rules. By adding these initial sums together, you are essentially preparing for the final step, where you assess the validity of the resulting sum in relation to the last digit of the DEA number.

The other options would not provide a logical or valid next step in this calculation process. Multiplying, subtracting, or dividing would disrupt the sequence required by the DEA number verification formula and wouldn’t align with the established method for ensuring a DEA number is correct.