There is an iron rod, 1/3 of it is used for the first time, and the remaining half of it is more than 1 meter used for the second time, and the result is 2.1 meters left. How many meters was the iron rod originally?
有一条铁棍，第一次用去它的(1/3)，第二次用去了余下的一半多1米，结果还剩2.1米．这条铁棍原来长多少米．
<gadget id="calculator">2.1 + 1</gadget>
<output>3.1</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3.1 / (1/2) / (2/3)</gadget>
<output>9.3</output>

<result>9.3</result>