truckload of coal was brought in from the cafeteria, with an average of 1.34 tons per day, and 8.4 tons left after 6 days of use. How many tons of coal did this car have?
食堂运来一车煤，平均每天用1.34吨，用了6天后还剩8.4吨．这车煤原来有多少吨？
<gadget id="calculator">1.34 * 6</gadget>
<output>8.04</output>

<gadget id="calculator">8.04 + 8.4</gadget>
<output>16.44</output>

<result>16.44</result>