There is a piece of wood, its full length (1/3) was used for the first time, and its full length (1/4) was used for the second time, leaving 3.5 meters. How many meters was this wood originally?
有一根木料，第一次用去全长的(1/3)，第二次用去全长的(1/4)，还剩3.5米，这根木料原长多少米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1 - (1/3) - (1/4)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">3.5 / (5/12)</gadget>
<output>8.4</output>

<result>8.4</result>