If the width of the rectangle is reduced by (1/3), how much must the length be increased to keep the area constant.
长方形的宽减少(1/3)，要使面积不变，长必须增加多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 * (2/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / (2/3)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">2 * (3/2)</gadget>
<output>3</output>

<gadget id="calculator">2 * 1</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

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

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

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