Lan Lan read extracurricular books, 18 pages each on the first and second days, and 40 pages in total on the third and fourth days. How many pages does she read on average per day?
兰兰看课外书，第一天和第二天每天各看18页，第三天和第四天一共看了40页．她平均每天看了多少页？
<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<gadget id="calculator">36 + 40</gadget>
<output>76</output>

<gadget id="calculator">76 / 4</gadget>
<output>19</output>

<result>19</result>