Write several consecutive natural numbers starting from 11 on the blackboard (such as 11, 12, 13...), and then erase one of the numbers, the average of the remaining numbers is 23. Ask how many natural numbers are erased?
在黑板上写了从11开始的若干个连续自然数(如11，12，13…)，后来擦掉了其中一个数，剩下的数的平均数是23．问擦掉的自然数是几？
<gadget id="calculator">648 - 618</gadget>
<output>30</output>

<result>30</result>