30 people eat, one rice bowl for one person, one vegetable bowl for two people, one soup bowl for three people, how many bowls should be prepared in total.
30人吃饭，1人一个饭碗，2人一个菜碗，3人一个汤碗，一共要准备多少个碗．
<gadget id="calculator">30 / 1</gadget>
<output>30</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<gadget id="calculator">30 + 15 + 10</gadget>
<output>55</output>

<result>55</result>