A calculator, if sold for 80 yuan, can earn 25% of the purchase price; if sold for 100 yuan. how much can you earn
一个计算器，若卖80元，可赚进货价的25%；若卖100元．则可赚多少
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">80 / (5/4)</gadget>
<output>64</output>

<gadget id="calculator">100 - 64</gadget>
<output>36</output>

<gadget id="calculator">36 / 64</gadget>
<output>9/16 = around 0.5625</output>

<result>9/16 = around 0.5625</result>