| 1 | A | B | C | D | E | F | G | H |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2 | Pythagorean tuning - Pythagorean intervals |  |  |  |  |  |  |  |
| 3 | Number of semitones | Generic names | Generic names | Generic names | Generic names | Specific names | Specific names | Specific names |
| 4 | Number of semitones | Quality and number | Quality and number | Other naming conventions | Other naming conventions | Pythagorean tuning | 5-limit tuning | 1/4-comma meantone |
| 5 | Number of semitones | Full | Short | Other naming conventions | Other naming conventions | Pythagorean tuning | 5-limit tuning | 1/4-comma meantone |
| 6 | 0 | - | - | comma | comma | Pythagorean comma (524288:531441) | - | diesis (128:125) |
| 7 | 0 | diminished second | d2 | (531441:524288) | - | - | - | diesis (128:125) |
| 8 | 1 | minor second | m2 | semitone, half tone, half step | diatonic semitone, minor semitone | limma (256:243) | - | - |
| 9 | 1 | augmented unison | A1 | semitone, half tone, half step | chromatic semitone, major semitone | apotome (2187:2048) | - | - |
| 10 | 2 | diminished third | d3 | tone, whole tone, whole step | tone, whole tone, whole step | - | - | - |
| 11 | 2 | major second | M2 | tone, whole tone, whole step | tone, whole tone, whole step | sesquioctavum (9:8) | sesquioctavum (9:8) | - |
| 12 | 3 | minor third | m3 | - | - | semiditone (32:27) | sesquiquintum (6:5) | - |
| 13 | 4 | major third | M3 | - | - | ditone (81:64) | sesquiquartum (5:4) | sesquiquartum (5:4) |
| 14 | 5 | perfect fourth | P4 | diatessaron | diatessaron | sesquitertium (4:3) | sesquitertium (4:3) | - |
| 15 | 6 | diminished fifth | d5 | tritone | tritone | - | - | - |
| 16 | 6 | augmented fourth | A4 | tritone | tritone | - | - | - |
| 17 | 7 | perfect fifth | P5 | diapente | diapente | sesquialterum (3:2) | sesquialterum (3:2) | - |
| 18 | 12 | (perfect) octave | P8 | diapason | diapason | duplex (2:1) | duplex (2:1) | duplex (2:1) |

Question: What is the quality number for this equation?
Answer: The Pythagorean comma's size (524288:531441) is the reciprocal of the Pythagorean diminished second's size (531441:524288).