There are 4 unequal natural numbers whose average is 10. What is the largest number among them.
有4个互不相等的自然数，它们的平均数是10．其中最大的数至少是多少．
<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 + 1</gadget>
<output>12</output>

<result>12</result>