The school cafeteria bought 165 bags of flour, with an average of 4 bags eaten every week. After 9 weeks, how many bags are left?
学校食堂买进165袋面粉，平均每周要吃掉4袋，9周后，还剩下多少袋？
<gadget id="calculator">4 * 9</gadget>
<output>36</output>

<gadget id="calculator">165 - 36</gadget>
<output>129</output>

<result>129</result>