Among the four-digit numbers composed of 1, 3, 5, and 8, how much is the largest number more than the smallest number?
用1、3、5、8组成的四位数中，最大的数比最小的数多多少．
<gadget id="calculator">8_531 - 1_358</gadget>
<output>7_173</output>

<result>7_173</result>