The school organizes an English competition. There are 180 participants in the fourth grade, 240 participants in the fifth grade, and 4/5 of the total number of participants in the sixth grade. How many participants in the sixth grade?
学校组织英语竞赛，四年级有180人参加，五年级有240人，六年级参加的人数是四、五年级总数的(4/5)，六年级有多少人参加？
<gadget id="calculator">180 + 240</gadget>
<output>420</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">420 * (4/5)</gadget>
<output>336</output>

<result>336</result>