Some children participated in the painting interest group, and the teacher gave everyone special drawing paper for drawing. If each person draws 7 pictures, the teacher still has 11 sheets of paper left; if half of the children draw 8 pictures each, and the other half draws 10 pictures each, there will be a difference of 13 papers in the end. May I ask: How many pieces are there in total? kid?
一些小朋友参加绘画兴趣小组，老师给大家发专用的图画纸用来画画．如果每个人画7张画，老师还能剩下11张纸；如果一半的小朋友每人画8张，另一半小朋友每人画10张，最后就会差13张纸，请问：一共有多少个小朋友？
<gadget id="calculator">11 + 13</gadget>
<output>24</output>

<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 - 7</gadget>
<output>2</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>