How to calculate school days for 4 terms. excluding weekends

Declare 
 @total int = 0,
 @counter int = 0,
 @strt date,
 @end date
Begin 
  set @total= (select distinct DATEDIFF(DAY,startdate,enddate) 
			from SchoolTerms
			 where EmisCode ='500226884' 
		   AND CurrentYear='2009'
		   AND Quater='Term1'	)
  set @strt=(Select Distinct StartDate
		   From SchoolTerms
		   where EmisCode ='500226884' 
		   AND CurrentYear='2009'
		   AND Quater='Term1')
  Set @end=(Select Distinct EndDate
		   From SchoolTerms
		   where EmisCode ='500226884' 
		   AND CurrentYear='2009'
		   AND Quater='Term1')
  while (@strt<@end) 
  BEGIN
	if DATEPART(weekday,@strt)=7  or DATEPART(weekday,@strt)= 1 
	begin
	    Declare @totals int = 0
 
	end
	else
	Begin
	
		set @counter+=1
		
		--print @counter
		--print DATEPART(weekday,@strt)
    end
    set @strt=dateadd(day,1,@strt)
    --
  End
  print @strt
  print @end
  print @counter
--print @total
End;

Msg 512, Level 16, State 1, Line 12
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
Msg 512, Level 16, State 1, Line 17
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.