FN-ROUND-004: ROUND takes ties away from zero on the 15-digit reading, so 1.005 rounds up
Excel differs from the mathematical answer · measured · recorded 2026-11-04
A tie in ROUND goes away from zero, not to even: ROUND(2.5,0) is 3 and ROUND(-2.5,0) is -3. The tie is judged on the 15-digit reading of FN-ROUND-002, not on the stored value. So 1.005 and 2.675, whose binary64 values lie just below the decimal tie, count as ties: ROUND(1.005,2) is 1.01 and ROUND(2.675,2) is 2.68, where rounding the stored value would give 1 and 2.67.
| Call and input route | Inputs | Excel | Correct value | Recorded in |
|---|---|---|---|---|
=ROUND(2.5,0)formula-literal | As typed | 30x4008000000000000 | — | Excel 16.0.20527.20088 Current Channel, Windows 64-bit (NT 10.0.26200), x86-64, AMD Ryzen 7 4800H, en-ZA |
=ROUND(-2.5,0)formula-literal | As typed | -30xc008000000000000 | — | Excel 16.0.20527.20088 Current Channel, Windows 64-bit (NT 10.0.26200), x86-64, AMD Ryzen 7 4800H, en-ZA |
=ROUND(2.675,2)formula-literal | As typed | 2.680x400570a3d70a3d71 | 2.670x40055c28f5c28f5c | Excel 16.0.20527.20088 Current Channel, Windows 64-bit (NT 10.0.26200), x86-64, AMD Ryzen 7 4800H, en-ZA |
=ROUND(1.005,2)formula-literal | As typed | 1.010x3ff028f5c28f5c29 | 10x3ff0000000000000 | Excel 16.0.20527.20088 Current Channel, Windows 64-bit (NT 10.0.26200), x86-64, AMD Ryzen 7 4800H, en-ZA |
Correct value: The stored value lies below the decimal tie, so the nearest multiple of 0.01 is the lower one; nearest binary64.
Correct value: The stored value lies below the decimal tie, so the nearest multiple of 0.01 is the lower one; nearest binary64.
Basis: The readings below, typed as literals, and the family rule of FN-ROUND-002 over the recorded ROUND rows.
Inferred: That every tie follows this is inferred from the rule's fit to the recorded rows; the literal ties read directly are the ones below.
Evidence and capture sources
- DnaCalc · crates/calc-func/tests/captures/cfunc_m3_2/oracle.capture.json 282f03144b9eb01b63207c1fecd74a726ad6e85f · the literal readings
- ExcelFunctionsHandbook · content/notes/evidence/2026-11-04/rounding-EVIDENCE.md b5d84a80a5a4640eca9ce04f232c0bc115503f34 · the fifteen-digit reading
- DnaCalc · crates/calc-func/tests/captures/cfunc_m3_2/oracle.capture.json 282f03144b9eb01b63207c1fecd74a726ad6e85f · sheet rounding_boundaries, row 8, column 4
- DnaCalc · crates/calc-func/tests/captures/cfunc_m3_2/oracle.capture.json 282f03144b9eb01b63207c1fecd74a726ad6e85f · sheet rounding_boundaries, row 9, column 4
- DnaCalc · crates/calc-func/tests/captures/cfunc_m3_2/oracle.capture.json 282f03144b9eb01b63207c1fecd74a726ad6e85f · sheet rounding_boundaries, row 19, column 4
- DnaCalc · crates/calc-func/tests/captures/cfunc_m3_2/oracle.capture.json 282f03144b9eb01b63207c1fecd74a726ad6e85f · sheet rounding_boundaries, row 21, column 4