12 people have a meal, 1 rice bowl for each person, 1 vegetable bowl for 2 people, 1 soup bowl for 4 people, how many bowls are needed in total.
12个人吃饭，每人1只饭碗，2人1只菜碗，4个人1只汤碗，一共需要多少只碗．
<gadget id="calculator">12 * 1</gadget>
<output>12</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">12 + 6 + 3</gadget>
<output>21</output>

<result>21</result>