If a triangle is enlarged by a ratio of 2:1, how many times its original area will be.
将一个三角形按2：1的比放大后，面积是原来的多少倍．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

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

<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<result>4</result>