Miyun Town built 17,600 meters of roads last year, 2,400 meters more than the previous year. How many meters were built last year and the year before?
密云镇去年修公路17600米，比前年修的多2400米．去年和前年共修了多少米？
<gadget id="calculator">17_600 - 2_400</gadget>
<output>15_200</output>

<gadget id="calculator">15_200 + 17_600</gadget>
<output>32_800</output>

<result>32_800</result>