A survey in Xining Primary School showed that the number of students with tooth decay accounted for 20% of the total number of students in the school, and the number of students without tooth decay accounted for 80%. Students with tooth decay accounted for ((())/(())) of all students in the school.
西宁小学的一项调查表明，有蛀牙的学生人数占全校学生人数的20%，没有蛀牙的学生人数占80%．有蛀牙的学生占全校学生的((())/(()))．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>