There are 240 students in the sixth grade of a certain elementary school, which is 60 fewer than the fifth grade. The number of students in the first to fourth grades accounts for 7/10 of the total number of students in the school. How many students are there in this school?
某小学六年级有学生240人，比五年级少60人，一至四年级学生人数占全校人数的(7/10)，这所学校共有多少人？
<gadget id="calculator">240 + 60 + 240</gadget>
<output>540</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">540 / (3/10)</gadget>
<output>1_800</output>

<result>1_800</result>