There are 140 students in the fifth grade of the experimental primary school. The number of fifth grade students is (1/6) of the total number of students in the whole school, and the number of fourth grade students is (4/21) of the total number of students in the whole school. How many students are there in the fourth grade?
实验小学五年级有学生140人，五年级学生数是全校学生总数的(1/6)，四年级学生数是全校学生总数的(4/21)，四年级有学生多少人？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">140 / (1/6)</gadget>
<output>840</output>

<gadget id="calculator">4 / 21</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">840 * (4/21)</gadget>
<output>160</output>

<result>160</result>