A paper mill produced 1.56 tons of paper in July, 1.68 tons of paper in August, and 0.74 tons less than the sum of July and August in September. How many tons of paper were produced in September?
某造纸厂七月份造纸1.56吨，八月份造纸1.68吨，九月份造纸数比七、八月份的和少0.74吨，九月份造纸多少吨？
<gadget id="calculator">1.68 - 0.74</gadget>
<output>0.94</output>

<gadget id="calculator">1.56 + 0.94</gadget>
<output>2.5</output>

<result>2.5</result>