A piece of iron sheet is 20 square meters, the first cut off this piece of iron sheet (1/8), the second cut off more than the first cut off this piece of iron sheet (1/4), and this piece of iron sheet is left What fraction of?
一张铁皮20平方米，第一次剪去这块铁皮的(1/8)，第二次剪去的比第一次剪去多这块铁皮的(1/4)，还剩这块铁皮的几分之几？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/8) + (1/4) + (1/8)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>