21 flowers are distributed to 5 people, each person has a different number of flowers, how many flowers at most?
21朵花分给5个人，每个人朵数不一样，最多几朵？
<gadget id="calculator">1 + 2 + 3 + 4</gadget>
<output>10</output>

<gadget id="calculator">21 - 10</gadget>
<output>11</output>

<result>11</result>