Xiao Ming goes shopping in Xingfuxing Supermarket. He brings 40 yuan and buys 8 bags of salt, each bag of salt is 3 yuan. How much money does Xiao Ming have left?
小明到兴福兴超市购物，他带了40元，买了8袋盐，每袋盐3元，小明还剩多少元？
<gadget id="calculator">3 * 8</gadget>
<output>24</output>

<gadget id="calculator">40 - 24</gadget>
<output>16</output>

<result>16</result>