The stationery store shipped 120 notebooks, and 8 packs of 10 notebooks have been sold. How many notebooks are left in the stationery store?
文具店运来120本笔记本，已经卖掉8包，每包10本，文具店还剩多少本笔记本没卖完？
<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">120 - 80</gadget>
<output>40</output>

<result>40</result>