The master and the apprentice start production at the same time, each making 100 parts. The master produces 25 parts per hour. When the master completes the task, the apprentice will have to work for an hour to complete the task. How many parts does the apprentice produce per hour?
师傅和徒弟同时开始生产，各要做100个零件，师傅每小时生产25个，当师傅完成任务时，徒弟还要做1小时才能完成任务．徒弟每小时生产零件多少个？
<gadget id="calculator">100 / 25</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<result>20</result>