Xiao Ming reads a book, on the first day he reads (2/5) of the whole book, on the second day he reads (2/3) of the first day, on the third day he reads the total (1/5) of the book in the previous two days /2), how much of this book did you read on the third day?
小明看一本书，第一天看了全书的(2/5)，第二天看的是第一天的(2/3)，第三天看的是前两天看的总数的(1/2)，第三天看了这本书的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/5) * (2/3)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(2/5) + (4/15)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/3) * (1/2)</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>