A fraction, the numerator is 21 greater than the denominator, equals (8/5) after the division, then what is the original fraction.
一个分数，分子比分母大21，约分后等于(8/5)，那么原分数是多少．
<gadget id="calculator">8 - 5</gadget>
<output>3</output>

<gadget id="calculator">21 / 3</gadget>
<output>7</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<gadget id="calculator">21 / 3 / 35</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">8 * (1/5)</gadget>
<output>8/5 = around 1.6</output>

<result>8/5 = around 1.6</result>