Class 4 and Class 2 participate in tree planting and divide them into several groups. If there are 5 people in a group, there will be 12 more people; if there are 7 people in a group, there will be 4 people short. How many people participated in the tree planting?
四2班参加植树，分成若干组，如果5人一组，还多出12人；如果7人一组，差4人．参加植树的有多少人？
<gadget id="calculator">12 + 4</gadget>
<output>16</output>

<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">5 * 8</gadget>
<output>40</output>

<gadget id="calculator">40 + 12</gadget>
<output>52</output>

<result>52</result>