Re: 1.356f+1.265f=2.6209998

The reason it does that is because of the way floating point numbers are represented. If you want to really understand why it's that result, you can look at Floating point - Wikipedia, the free encyclopedia. Basically it boils down to floating points not being able to exactly represent 1.356f or 2.621f exactly, and because computers almost always use truncation instead of rounding, you get a number smaller than 2.621f (the actual answer).

1.356f = 0x3FAD9168 = 1.3559999 (slightly smaller than 1.356)

1.265f = 0x3FA1EB85 = 1.2650000 (exact)

2.621f = 0x4027BE76 = 2.6209998 (slightly smaller than 2.621)