piece of iron wire, after cutting off (2/9), there are 28 meters left. How long is this iron wire?
一根铁丝，截去(2/9)后，还剩28米，这根铁丝原来有多长？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9)</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">28 / (7/9)</gadget>
<output>36</output>

<result>36</result>