After adding one of its fractional units to a fraction, the value is 1, and after subtracting one of its fractional units, the value is (2/3), what is the fraction.
一个分数加上它的一个分数单位后，值是1，减去它的一个分数单位后，值是(2/3)，这个分数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) / 2</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/6)</gadget>
<output>5/6 = around 0.833333</output>

<result>5/6 = around 0.833333</result>