Rounding differences in formula vs. hand-entered

Originally Posted by shg

Your computer, and therefore Excel, use a binary floating point format to store numbers. That format cannot store most decimals exactly, in the same sense that a finite base-10 decimal can't be exactly equal to 1/3. When you add or subtract inexact numbers, you frequently get even less exact numbers.

These numbers are pretty far from being inexact; they're all rational numbers. There's no "1/3" being forced to decimal, for example.

Originally Posted by shg

The manually-entered 99.1 value in F9 is stored as 4058C66666666666 (the hex representation of the 64-bit double-precision number). The SUM formula in F3 returns the result 4058C66666666667; it differs in the least significant bit.

If I understand you correctly, you're saying that a result of 0.9 is stored differently if it's the result of a calculation versus a hand-entered number?