Uncle Li bought 2 bags of monosodium glutamate in the supermarket, paid the salesperson 30 yuan, and got 4 yuan back. How much is an average bag of MSG?
李大爷在超市买了2袋味精，付给营业员30元，找回了4元．平均每袋味精多少元？
<gadget id="calculator">30 - 4</gadget>
<output>26</output>

<gadget id="calculator">26 / 2</gadget>
<output>13</output>

<result>13</result>