Numbers lower than 100 = solo instruments

200 = duets

300 = trios

400 = quartets

continue in this pattern until 900 = nonets

1000 + = large ensembles

1500 + = vocal music

Call numbers for solo piano have some helpful rhythmic divisions:

M 28 - Marches

M 30 - Dances (general)

M 31 - Two-rhythm (polka, etc.)

M 32 - Three-rhythm (waltz, etc.)

Some call numbers for larger ensembles with dance designation:

M 1047 - Dances (general) for orchestra

M 1048 - Two-rhythm (polka, etc.) for orchestra

M 1049 - Three-rhythm (waltz, etc.) for orchestra

M 1147 - Dances (general) for string orchestra

M 1148 - Two-rhythm (polka, etc.) for string orchestra

M 1149 - Three-rhythm (waltz, etc.) for string orchestra

M 1247 - Marches for band (original compositions)

M 1247.9 - Dances (general) for band (original)

M 1248 - Two-rhythm (polka, etc.) for band (original)

M 1249 - Three-rhythm (waltz, etc.) for band (original)

M 1260 - Marches for band (arrangements)

M 1262 - Dances (general) for band (arrangements)

M 1264 - Two-rhythm (polka, etc.) for band (arrangements)

M 1266 - Three-rhythm (waltz, etc.) for band (arrangements)

M 1356 - Dance orchestra or ensemble

M 1356.2 - Lead sheets for dance orchestras

M 1450 - Folk dances with directions that include music, unspecified region

M 1627 - 1853 - Folk music by region (Dance music may be included)