Friendship Mall sold an average of 9 TVs per day from July to September. How many TVs were sold in total in the past three months?
友谊商场7-9月份平均每天售出电视机9台，这三个月一共售出电视机多少台？
<gadget id="calculator">31 + 31 + 30</gadget>
<output>92</output>

<gadget id="calculator">9 * 92</gadget>
<output>828</output>

<result>828</result>