How many different three-digit numbers can be formed with the three numbers 2, 4 and 6 (numbers cannot be used repeatedly).
用2、4和6三个数字组成多少个不同的三位数(数字不能重复使用)．
<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<result>6</result>