There are 3 tons of coal in the cafeteria. On average, (3/7) tons are burned every day. How many days can it be burned?
食堂有煤3吨，平均每天烧(3/7)吨，可以烧多少天．
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">3 / (3/7)</gadget>
<output>7</output>

<result>7</result>