Hope Primary School has 120 students in the fifth grade and 135 students in the sixth grade. These two grades account for 3/7 of the total number of students in the school. How many students are there in the whole school?
希望小学五年级有学生120人，六年级有学生135人，这两个年级的人数占全校总人数的(3/7)，全校共有多少人？
<gadget id="calculator">120 + 135</gadget>
<output>255</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">255 / (3/7)</gadget>
<output>595</output>

<result>595</result>