A steel pipe, the full length (1/2) is used up for the first time, and the full length (1/3) is used up for the second time, what fraction of the full length is left?
一根钢管，第一次用去了全长的(1/2)，第二次用去了全长的(1/3)，还剩下全长的几分之几？
<gadget id="calculator">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">(1/2) + (1/3)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 - (5/6)</gadget>
<output>1/6 = around 0.166667</output>

<result>1/6 = around 0.166667</result>