piece of wood, (2/5) is used for the first time, and the remaining (3/5) is used for the second time, leaving (1/2) meters. How long is this log in meters?
一根木料，第一次用去(2/5)，第二次用去余下的(3/5)，还剩(1/2)米．这根木料全长多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) * (3/5)</gadget>
<output>9/25 = around 0.36</output>

<gadget id="calculator">1 - (2/5) - (9/25)</gadget>
<output>6/25 = around 0.24</output>

<gadget id="calculator">(1/2) / (6/25)</gadget>
<output>25/12 = around 2.083333</output>

<result>25/12 = around 2.083333</result>