Xiaohua borrowed a 180-page book, and read an average of 45 pages a day in the first 3 days. How many pages should I read on the 4th day?
小华借了一本180页的书，前3天平均每天看45页，第4天应该从第多少页看起．
<gadget id="calculator">45 * 3</gadget>
<output>135</output>

<gadget id="calculator">135 + 1</gadget>
<output>136</output>

<result>136</result>