Add a number to the numerator and denominator of (1/15), so that the obtained fraction can be reduced to (1/3), find this number.
把(1/15)的分子、分母，同时加上一个数字，使所得的分数可以约简为(1/3)，求这个数．
<gadget id="calculator">3 / 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">15 / 1</gadget>
<output>15</output>

<gadget id="calculator">(1/3) * 15</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

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

<result>6</result>