From 9:00 am to 9:30 am on Sunday, Xiao Pang and Xiao Ding Ding had a typing competition. Xiao Pang typed 2,400 words, and Xiao Ding Ding typed 2,730 words. What is the average difference between their typing words per minute?
星期天上午9：00～9：30，小胖和小丁丁两人比赛打字，小胖打了2400个字，小丁丁打了2730个字，他们平均每分钟打的字相差多少个？
<gadget id="calculator">2_730 / 30</gadget>
<output>91</output>

<gadget id="calculator">2_400 / 30</gadget>
<output>80</output>

<gadget id="calculator">91 - 80</gadget>
<output>11</output>

<result>11</result>