How many four-digit odd numbers without repeated numbers can be formed from the numbers 1, 2, 3, 4, 5, and 6.
由数字1，2，3，4，5，6共可组成多少个没有重复数字的四位奇数．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">6 * 5 * 4 * (3/2)</gadget>
<output>180</output>

<result>180</result>