From A to B, A travels the whole journey (1/8) per hour, and B travels the whole journey (1/7) per hour. How many hours does B take less than A to complete the journey.
从甲地到乙地，甲每小时行全程的(1/8)，乙每小时行全程的(1/7)，行完全程乙比甲少用多少小时．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / (1/8)</gadget>
<output>8</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / (1/7)</gadget>
<output>7</output>

<gadget id="calculator">8 - 7</gadget>
<output>1</output>

<result>1</result>