Grandma buys 4 bags of milk and 2 breads, pays the salesperson 20 yuan, gets back 5.2 yuan, and each bread is 5.4 yuan. How much is each bag of milk?
奶奶买4袋牛奶和2个面包，付给售货员20元，找回5.2元，每个面包5.4元，每袋牛奶多少元？
<gadget id="calculator">20 - 5.2</gadget>
<output>14.8</output>

<gadget id="calculator">5.4 * 2</gadget>
<output>10.8</output>

<gadget id="calculator">14.8 - 10.8</gadget>
<output>4</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<result>1</result>