For three consecutive natural numbers, divide the largest number by the smallest number, the quotient is 1 (1/7), what is the middle number?
三个连续自然数，用最小的数除最大的数，商是1(1/7)，中间的数是多少．
<gadget id="calculator">8 / 7</gadget>
<output>8/7 = around 1.142857</output>

<gadget id="calculator">1 + (8/7)</gadget>
<output>15/7 = around 2.142857</output>

<gadget id="calculator">(8/7) - 1</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(15/7) / (1/7)</gadget>
<output>15</output>

<result>15</result>