--(1)

select * from
(
select *,
ROW_NUMBER()over(order by FId asc) as Rnumber
from MyStudents
)
as Tbl3
where Rnumber between (3*7+1) and 3*8

--(2)

select top 3 * from MyStudents
where FId not in
(select top (3*7) FId from MyStudents 
order by FId )
order by FId