Try this code
Create table #temp
(Id int identity(1,1),
quantity int,
a1 int,
b1 int,
c1 int,
d1 int
)
insert into #temp Values (5,4,10,11,9),(4,2,8,11,9),(6,3,10,1,9)
SELECT Id, quantity,(a1*quantity) as A1,(b1*quantity) as B1,(c1*quantity) as C1,
(d1*quantity) as D1 from #temp
DROP table #temp