If the length of the rectangle increases (1/5) and the width increases (1/4), how much does its area increase from the original
长方形的长增加(1/5)，宽增加(1/4)，那么它的面积比原来增加多少
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) - 1</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>