A coal mine can excavate 9 tons of coal per day. How many tons of coal can be excavated in the fourth quarter of this year?
一个煤矿，每天可挖煤9吨，今年第四季度可挖煤多少吨？
<gadget id="calculator">31 + 30 + 31</gadget>
<output>92</output>

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

<result>828</result>