The store usually sells a football for 39 yuan, and can earn 30%. Now it sells it for 24.5 yuan. Is it a profit or a loss? How much to lose or earn?
商店平时39元卖出一个足球，可赚30%，现在以24.5元卖出，是赚还是赔？赔或赚多少？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">39 / (13/10)</gadget>
<output>30</output>

<gadget id="calculator">30 - 24.5</gadget>
<output>5.5</output>

<result>5.5</result>