There are 100 students in the first grade of a certain elementary school, which is more than the second grade (1/4). The number of students in the first and second grades accounts for 30% of the total number of students in the school. How many students are there in the whole school?
某小学一年级有学生100人，比二年级多(1/4)，一、二年级人数占全校总人数的30%，全校共有学生多少人？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">100 / (5/4)</gadget>
<output>80</output>

<gadget id="calculator">100 + 80</gadget>
<output>180</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">180 / (3/10)</gadget>
<output>600</output>

<result>600</result>