Find the law and fill in the numbers: (1/4), (3/10), (7/20), (2/5), how many.
找规律填数：(1/4)，(3/10)，(7/20)，(2/5)，多少．
<gadget id="calculator">9 / 8</gadget>
<output>9/8 = around 1.125</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(9/8) * (2/5)</gadget>
<output>9/20 = around 0.45</output>

<result>9/20 = around 0.45</result>