Can't get my head around this one (perhaps it's just Friday!)

Cell B15 has a simple formula (Adding two cells)
Cell B16 shaves off a couple of numbers number =CONCATENATE(RIGHT
(B15,3))
B17 has a number I want to match with the shaved off number in B16

But when I try to add to that a conditional statement...
=IF(B17<B16,"match","no match")

Eg...

A1: 1221
A2: 1
B15: = A1+A2
B16: =CONCATENATE(RIGHT(B15,3)) [yelids 222]
B17: 223
B18 =IF(B17<B16,"match","no match")

I shoud get "no match" in B18 [222 does not equal 223) but I get the
same value no matter what is in B16 or B17. Is the concatenate
formula causing a problem? I know the sum feature does not work with
it.

Thanks in advance to any wiz who can figure this one out!