Simple (?) SUMIF Problem...

I'm a bit new to most worksheet functions in Excel, so I've been manually writing IF statements out for ranges of data that could easily be done with a little array work. So I set out to convert all my functions into something more readable and quicker to write.

But I ran into a problem. I want to add the values of an array G45:Z45 if the corresponding values in G44:Z45 are less than or equal to P41. So I thought to use a SUMIF:

=SUMIF(G44:Z45,<=+P41,G45:Z45)

That didn't work, in fact, it didn't come error free until I did:

=SUMIF(G44:Z45,"<="+P41,G45:Z45)

But that doesn't add anything up either. From what I can see, the problem lies within the condition. If I simply put P41, it works. The moment I add <= I get a multitude of problems.