Xiaohua reads a book, and has already read the whole book (7/9), how much of it is left?
小华看一本书，已经看了全书的(7/9)，还剩几分之几没有看？
<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 - (7/9)</gadget>
<output>2/9 = around 0.222222</output>

<result>2/9 = around 0.222222</result>