The third-grade students visited the Science and Technology Museum. They lined up in 4 teams, and each team had the same number of people. Xiaoying is in the second team. She is the 9th person from the front and the 11th person from the back. How many people came to visit the exhibition?
三年级学生到科技馆参观，大家排成4队，每队的人数同样多．小莹排在第2队，从前面数是第9人，从后面数是第11人，去参观展览的共有多少人？
<gadget id="calculator">11 - 1</gadget>
<output>10</output>

<gadget id="calculator">9 + 10</gadget>
<output>19</output>

<gadget id="calculator">19 * 4</gadget>
<output>76</output>

<result>76</result>