The water consumption of Daqiao Elementary School in the four quarters of last year: 189 tons in the first quarter, 204 tons in the second quarter, 351 tons in the third quarter, and 156 tons in the fourth quarter. How many tons did this elementary school use per month on average last year?
大桥小学去年四个季度用水情况：第一季度189吨，第二季度204吨，第三季度351吨，第四季度156吨，这个小学去年平均每个月用水多少吨？
<gadget id="calculator">189 + 204 + 351 + 156</gadget>
<output>900</output>

<gadget id="calculator">900 / 12</gadget>
<output>75</output>

<result>75</result>