Former Excel developer here. In Excel 97, the difference between the values needed to be less than 1e-16 times the magnitudes of the operands to be considered e

Former Excel developer here. In Excel 97, the difference between the values needed to be less than 1e-16 times the magnitudes of the operands to be considered equal. It makes sense since such a small proportion is unlikely to occur by chance through arithmetic without the values being "equal" in the original base.