Xiaofang finished reading a story book in three weeks. Those who read the whole book in the first and second weeks (3/4), those who read the whole book in the second and third weeks (5/7). How much did I read the whole book in the second week?
小芳用三周看完了一本故事书．第一、二周看了全书的(3/4)，第二、三周看了全书的(5/7)．第二周看了全书的多少．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) - 1</gadget>
<output>-2/7 = around -0.285714</output>

<gadget id="calculator">(3/4) + (-2/7)</gadget>
<output>13/28 = around 0.464286</output>

<result>13/28 = around 0.464286</result>