How many three-digit numbers can be formed from the numbers 1, 2, 3, and 4 without repeating numbers?
由数字1、2、3、4可以组成多少个没有重复数字的三位数字．
<gadget id="calculator">4 * 3 * 2 * 1</gadget>
<output>24</output>

<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">24 / 6</gadget>
<output>4</output>

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<result>24</result>