Xiao Ming reads a 140-page popular science book. He reads (1/7) on the first day and the rest (1/6) on the second day. How many pages did he read on the second day?
小明读一本140页的科普读物，第一天读(1/7)，第二天读余下的(1/6)，第二天读了多少页？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

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

<gadget id="calculator">140 * (6/7) * (1/6)</gadget>
<output>20</output>

<result>20</result>