Excel IF function shows incorrect result

I made a sheet which calculates columns of numbers. Cell A1 adds column A and cell B1 ads column B. But to make this explanation as simple as possible, lets just say that column A equals exactly 5 in cell A1 (A1=5), and column B equals exactly 5 in cell B1 (B1=5).

Somewhere else in the sheet (let's say cell C5) I need to compare the results in cell A1 and B1 and IF they are equal, I need a TRUE result. This is the formula in cell C5: =IF(A1=B1,TRUE,FALSE)

Given that A1=5 and B1=5, the result in C5 should be TRUE. The problem I'm having is that Excel is returning FALSE when cells A1 and B1 ARE BOTH EQUAL TO EXACTLY 5.

Example of the SHEET, I hope this helps: (the periods are to keep their places, otherwise when you post the spaces go away)

........ A.......B.......C........D
1.......5........5.......5
2
3
4
5......................FALSE (FALSE is in cell C5) < the formula in cell C5 is =IF(A1=B1,TRUE,FALSE)
6

And if I re-write cell C5 formula (with cell A1 and cell B1 still exactly equal to 5): =IF(A1<>B1,TRUE,FALSE) it returns a TRUE.

I typed a 5 in A1 and B1 (so they are exactly equal to 5 no decimal spaces) and I'm still getting the incorrect FALSE.

I am using Excel 2013 on a Windows 8 PC.

I am at a complete loss. Did I accidentally hit a CONTROL or ALT shortcut KEY that is making Excel return a negative (opposite) result?