Xiaoli plans to finish reading a book (2/3) in three days. She reads the whole book (2/5) on the first day and (1/6) on the second day. How much does she read on the third day? ? List the formula: how much.
小丽计划用三天看完一本书的(2/3)，她第一天看了全书的(2/5)，第二天看了(1/6)，那么第三天看了多少？列出算式：多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/5) - (1/6)</gadget>
<output>7/30 = around 0.233333</output>

<gadget id="calculator">(2/3) - (7/30)</gadget>
<output>13/30 = around 0.433333</output>

<result>13/30 = around 0.433333</result>