Xiaoxing reads an extra-curricular book. On the first day, he reads 15% of the whole book, and on the second day, he reads 20% of the whole book. In two days, he reads 70 pages in total. How many pages are left?
小星看一本课外书，第一天看了全书的15%，第二天看了全书的20%，两天共看了70页，还剩下多少页没看完．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/20) + (1/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">70 / (7/20)</gadget>
<output>200</output>

<gadget id="calculator">200 - 70</gadget>
<output>130</output>

<result>130</result>