A batch of saplings were planted. It was originally planned that 40 people would participate, and each person would plant 12 saplings. Later, some people were added, and as a result, 4 fewer trees were planted. How many people have been added?
栽一批树苗，原计划40参加，每人栽12棵．后来又增加了一些人，结果少栽4棵．增加了多少人？
<gadget id="calculator">12 - 4</gadget>
<output>8</output>

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

<gadget id="calculator">12 * 5</gadget>
<output>60</output>

<gadget id="calculator">60 - 40</gadget>
<output>20</output>

<result>20</result>