Xiaohong reads a story book. She reads (3/7) of the whole book on the first day, (1/4) of the whole book on the second day, and reads the rest on the third day. How much of the whole book did you read on the third day?
小红看一本故事书，第一天看了全书的(3/7)，第二天看了全书的(1/4)，剩下的第三天看完．第三天看了全书的几分之几？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (3/7) - (1/4)</gadget>
<output>9/28 = around 0.321429</output>

<result>9/28 = around 0.321429</result>