If an electronic watch displays 6:20:25 at 6:20:25, then how many situations in which the 5 numbers displayed on the watch are different in one hour from 5:00 to 6:00.
某电子表在6时20分25秒时，显示6：20：25，那么从5时到6时这1个小时里，此表显示的5个数字都不相同的情况共有多少种．
<gadget id="calculator">5 * 4 * 7 * 6</gadget>
<output>840</output>

<result>840</result>