A science book has 320 pages. Xiaohong reads 18 pages a day for a week. How many pages are left?
一本科技书有320页，小红看了一周，每天看18页，还剩下多少页没看？
<gadget id="calculator">7 * 18</gadget>
<output>126</output>

<gadget id="calculator">320 - 126</gadget>
<output>194</output>

<result>194</result>