piece of wood is used up (1/5), and there is still (4/3) meters left, how many meters is the length of this piece of wood?
一根木料用去(1/5)，还剩(4/3)米，这根木料长多少米．
<gadget id="calculator">4 / 3</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/3) / (4/5)</gadget>
<output>5/3 = around 1.666667</output>

<result>5/3 = around 1.666667</result>