In the Yushu protest and disaster relief donation activity, each of the three sixth grade classes of a certain school donated 180 yuan, and the two fifth grade classes donated a total of 300 yuan. How much is the total donation for the fifth and sixth grades of this school?
在玉树抗争救灾捐款活动中，某校六年级三个班每班都捐款180元，五年级两个班共捐款300元．这个学校的五、六年级一共捐款多少元？
<gadget id="calculator">180 * 3</gadget>
<output>540</output>

<gadget id="calculator">540 + 300</gadget>
<output>840</output>

<result>840</result>