Question 357586
Since "There are 28 students in a mathematics class" and "one-fourth of the students are called to the guidence office", this means that {{{(1/4)28=28/4=7}}} students are called to the guidence office. So there are {{{28-7=21}}} students left.



Since "one-third of the remaining students are called to the nurses office", we know that {{{(1/3)21=21/3=7}}} students are called to the nurses office. So there are {{{21-7=14}}} students left.



Finally, because "one-half of those left to go to the library", there are {{{(1/2)14=14/2=7}}} students who went to the library. So there are {{{14-7=7}}} students left in the class.