There are two items in a store, one of which is sold at a 25% cost increase, and the other is sold at a 20% decrease in cost, and the selling prices are exactly the same, then the sum of the selling prices of the two items is a fraction of the sum of the costs of the two items ?
某商店有两件商品，其中一件商品成本增加25%出售，一件商品按成本减少20%出售，售价恰好相同，那么两件商品售价总和是两件商品成本总和的几分之几？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<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">1 / (5/4)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">(4/5) + (5/4)</gadget>
<output>41/20 = around 2.05</output>

<gadget id="calculator">2 / (41/20)</gadget>
<output>40/41 = around 0.97561</output>

<result>40/41 = around 0.97561</result>