A bundle of iron wire, 40% is used up for the first time, and 25% is used up for the second time, leaving 28 meters. How long is the bundle of wires in meters?
一捆铁丝，第一次用去40%，第二次用去25%，还剩下28米，这捆铁丝长多少米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">28 / (7/20)</gadget>
<output>80</output>

<result>80</result>