The number of students in the fifth grade of a certain elementary school is 125% of the number of students in the fourth grade, and the number of students in the fifth grade is 25% less than that of the sixth grade. There are 400 students in the sixth grade. How many students are there in the fourth grade?
某小学五年级学生人数是四年级学生人数的125%，五年级学生人数比六年级学生人数少25%，六年级共有学生400人，问四年级有多少个学生？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">125 / 100</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(3/4) / (5/4)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">400 * (3/5)</gadget>
<output>240</output>

<result>240</result>