A piece of steel, (2/5) is used for the first time, and the remaining (3/5) is used for the second time, leaving (1/2) meter, what is the total length of this steel in meters?
一根钢材，第一次用去(2/5)，第二次用去余下的(3/5)，还剩下(1/2)米，这根钢材全长多少米．
<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>