A canteen used 5.07 tons of coal in January, 4.5 tons of coal in February, and 3.07 tons less than the sum of the previous two months in March. How many tons of coal was used in March?
某食堂1月份用煤5.07吨，2月份用煤4.5吨，3月份用煤比前两个月的总和少3.07吨，3月份用煤多少吨？
<gadget id="calculator">4.5 - 3.07</gadget>
<output>1.43</output>

<gadget id="calculator">5.07 + 1.43</gadget>
<output>6.5</output>

<result>6.5</result>