Among the three fractions (7/9), (2/5), and (5/6), what is the smallest fraction unit?
在(7/9)、(2/5)、(5/6)这三个分数中，分数单位最小的一个是多少
<gadget id="calculator">9 / 1</gadget>
<output>9</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<result>7/9 = around 0.777778</result>