During class exercises, Wang Peng stands in the 5th column from the right, the 12th column from the left, the 7th from the front, and the 21st from the back. The number of people in each row and column is the same. How many students do exercises in total?
课间操时，王朋站在右边起第5列，左边起第12列，从前面数是第7个，从后面数是第21个，每行每列的人数相同．做操的学生一共有多少人？
<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">5 + 11</gadget>
<output>16</output>

<gadget id="calculator">21 - 1</gadget>
<output>20</output>

<gadget id="calculator">7 + 20</gadget>
<output>27</output>

<gadget id="calculator">16 * 27</gadget>
<output>432</output>

<result>432</result>