Xiao Fang reads a 200-page classic book, and has already read 140 pages, and the rest must be finished within 4 days. How many pages do you read on average per day?
小方看一本200页的经典读本，已经看了140页，剩下的要在4天内看完．平均每天看多少页？
<gadget id="calculator">200 - 140</gadget>
<output>60</output>

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<result>15</result>