Jiajia reads a 208-page science fiction book. She reads 17 pages a day for the first 4 days, and then reads 20 pages a day. How many days will it take Jiajia to finish it?
佳佳看一本208页的科幻书，前4天每天看了17页，以后每天看20页，佳佳再用几天才能看完？
<gadget id="calculator">17 * 4</gadget>
<output>68</output>

<gadget id="calculator">208 - 68</gadget>
<output>140</output>

<gadget id="calculator">140 / 20</gadget>
<output>7</output>

<result>7</result>