The numerator of a simplest fraction is expanded by 5 times and the denominator is reduced by 4 times. The numerator is the smallest prime number and the denominator is the largest composite number less than 10. What is the original simplest fraction?
一个最简分数的分子扩大5倍，分母缩小4倍后，分子是最小的质数，分母是小于10的最大合数，原来这个最简分数是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">(2/5) / 36</gadget>
<output>1/90 = around 0.011111</output>

<result>1/90 = around 0.011111</result>