Yucai Primary School has 1,200 students, among which the number of students in the lower grades accounts for 2/5 of the total number of students in the school, the ratio of the number of students in the middle grades to the number of students in the lower grades is 5:6, how many students are there in the upper grades?
育才小学有学生1200人，其中低年级学生人数占全校学生总数的(2/5)，中年级学生人数与低年级学生人数的比是5：6，高年级有学生多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(2/5) * (5/6)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (2/5) - (1/3)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1_200 * (4/15)</gadget>
<output>320</output>

<result>320</result>