(2/10) meters are used up for a piece of iron wire, and (8/10) meters are left, what is the original length of this iron wire
一根铁丝用去(2/10)米，还剩(8/10)米，这根铁丝原来长多少米
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">8 / 10</gadget>
<output>4/5 = around 0.8</output>

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

<result>1</result>