Wenwen has been reading a 210-page storybook for 6 days, with an average of 28 pages per day. How many pages are left?
文文看一本210页的故事书已经看了6天，平均每天看28页，还有多少页没看？
<gadget id="calculator">28 * 6</gadget>
<output>168</output>

<gadget id="calculator">210 - 168</gadget>
<output>42</output>

<result>42</result>