Given a fraction, if only the numerator increases by 5, then the value of the fraction increases by 0.5; if only the denominator increases by 5, then the value of the fraction decreases by 0.3, then what is the original fraction.
已知一个分数，如果只有分子增加5，那么分数的值增大了0.5；如果只有分母增加5，那么分数的值减小了0.3，那么原来的分数是多少．
<gadget id="calculator">5 / 0.5</gadget>
<output>10</output>

<gadget id="calculator">0.3 * 10</gadget>
<output>3</output>

<gadget id="calculator">0.3 * 5</gadget>
<output>1.5</output>

<gadget id="calculator">3 + 1.5</gadget>
<output>4.5</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 10</gadget>
<output>1</output>

<gadget id="calculator">(1/10) * 5</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) - 1</gadget>
<output>-1/2 = around -0.5</output>

<gadget id="calculator">1 + (-1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4.5 / (1/2) / 10</gadget>
<output>0.9</output>

<result>0.9</result>