Calculated Columns Based On Multiple Columns?

MS SQL 2008 R2

I have the following effectively random numbers in a table:

n1,n2,n3,n4,SCORE
1,2,5,9,i
5,20,22,25,i
6,10,12,20,i

I'd like to generate the calculated column SCORE based on various scenarios in the other columns. eg.

if n1<10 and n2<10 then i=i + 1
if n4-n3=1 then i=i + 1
if more than 2 consecutive numbers then i=i + 1

So, I need to build the score. I've tried the procedure below and it works as a pass or fail but is too limiting. I'd like something that increments the variable @test1.

declare @test1 int
set @test1=0
select top 10 n1,n2,n3,n4,n5,n6,
case when (
n1=2 and
n2>5
)
then @test1+1
else @test1
end as t2
from
allNumbers