Among the four fractions (1/2), (2/3), (7/9) and (11/13), what is the smallest fraction unit?
在(1/2)、(2/3)、(7/9)和(11/13)这四个分数中，分数单位最小的一个是多少
<gadget id="calculator">13 / 1</gadget>
<output>13</output>

<gadget id="calculator">11 / 13</gadget>
<output>11/13 = around 0.846154</output>

<result>11/13 = around 0.846154</result>