On Children's Day, the Science and Technology Museum organizes special activities for students. 1800 people visited in the morning and 2160 people visited in the afternoon. For every 40 people, a volunteer will be sent to explain to the students. How many more volunteers were sent in the afternoon than in the morning? (column solution)
六一儿童节时，科技馆组织学生专场活动．上午有1800人参观，下午有2160人参观．每40人就派一名志愿者给同学们进行讲解．下午比上午多派出几名志愿者？(列式解答)
<gadget id="calculator">2_160 / 40</gadget>
<output>54</output>

<gadget id="calculator">1_800 / 40</gadget>
<output>45</output>

<gadget id="calculator">54 - 45</gadget>
<output>9</output>

<result>9</result>