How many ways to arrange the four numbers 2, 4, 5, and 7 into four digits that are multiples of 3 and 5?
把2，4，5，7四个数字排成既是3的倍数，又是5的倍数的四位数，共有多少种排法．
<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<result>6</result>