Adding a number to the numerator of (11/61), and subtracting the same number from the denominator, the resulting fraction can be divided into (2/7). What is this number?
(11/61)的分子加上一个数，分母减去同一个数，所得的分数约分后得(2/7)．这个数是多少？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) * 61</gadget>
<output>122/7 = around 17.428571</output>

<gadget id="calculator">(122/7) - 11</gadget>
<output>45/7 = around 6.428571</output>

<gadget id="calculator">1 + (2/7)</gadget>
<output>9/7 = around 1.285714</output>

<gadget id="calculator">(45/7) / (9/7)</gadget>
<output>5</output>

<result>5</result>