If (2/9) meters are cut off from a ribbon, (4/9) meters remain, what is the total length of the ribbon?
一根丝带剪掉(2/9)米还剩(4/9)米，这根丝带原来全长多少米．
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(2/9) + (4/9)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>