50% of a number is as much as 80% of 70. What is the number?
一个数的50%与70的80%一样多，这个数是多少．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/5) / (1/2)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">70 * (8/5)</gadget>
<output>112</output>

<result>112</result>