Master He is on duty every 6 days, and Master Chen is on duty every 8 days. They are on duty at the same time today. How many days will it take for them to be on duty at the same time?
何师傅每隔6天值一次班，陈师傅每隔8天值一次班，今天他们同时值班，至少要过多少天他们又同时值班？
<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<result>63</result>