Mom plans to order 2 bottles of milk for Xiaoqing every day in November. The wholesale price is 126 yuan, and the retail price is 3 yuan per bottle. How much cheaper is the wholesale price of each bottle of milk than the retail price?
妈妈准备11月每天给小青预订2瓶牛奶，按批发价需要126元，零售价每瓶3元，每瓶牛奶批发价比零售价便宜多少元？
<gadget id="calculator">2 * 30</gadget>
<output>60</output>

<gadget id="calculator">126 / 60</gadget>
<output>21/10 = around 2.1</output>

<gadget id="calculator">3 - (21/10)</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>