Divide the whole class into groups of 7, 8, and 9, and ask how many students there are in the class?
将全班同学分成7人一组，8人一组，9人一组都差了一人，问全班有同学多少人？
<gadget id="calculator">494 - 1</gadget>
<output>493</output>

<result>493</result>