There are several consecutive odd numbers starting from 1 written on the blackboard: 1, 3, 5, 7, ..., after erasing one of the odd numbers, the sum of all remaining odd numbers is 100, so what is the odd number erased?
黑板上写有从1开始的若干个连续的奇数：1，3，5，7，…，擦去其中的一个奇数以后，剩下的所有奇数之和为100，那么擦去的奇数是多少．
<gadget id="calculator">11 ** 2</gadget>
<output>121</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">121 - 100</gadget>
<output>21</output>

<result>21</result>