Students in the third grade group participated in the group gymnastics performance on the "June 1st" Festival. There are the same number of people in each horizontal row, and the same number of people in each vertical row. Wang Jing's position is the 10th from the left, the 8th from the right, the 9th from the front, and the 7th from the back. How many students participated in the performance?
三年级组同学参加"六一"节团体操表演，每横排人数同样多，每竖排人数也同样多．王菁的位置是从左数第10人，从右数第8人，从前数第9人，从后数是第7人．参加表演的同学有多少人．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">10 + 7</gadget>
<output>17</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">9 + 6</gadget>
<output>15</output>

<gadget id="calculator">17 * 15</gadget>
<output>255</output>

<result>255</result>