Tuplets indicate where a beat is divided into a different number of subdivisions than is usually expected according to the current meter. They can be used to fit more notes or fewer notes in a beat than usually exist in a beat, according to the usual pattern of subdivision.

Because these subdivisions are not standard but tuplet notes use the same rhythmic notation as normal notes, tuplets must be clearly marked to show that their rhythmic duration is different.

In the following examples, the triplet quarter notes are shown under a bracket with the number 3. The duplet eighth notes do not need a bracket as they are joined by a beam, which has a number 2 above it.

Figure 1. A 4/4 bar with the standard subdivision of four quarter notes
Figure 2. A 4/4 bar with a subdivision of six triplet quarter notes in the space of four regular quarter notes
Figure 3. A 6/8 bar with the standard subdivision of six eighth notes
Figure 4. A 6/8 bar with a subdivision of four duplet eighth notes in the space of six regular eighth notes

In Dorico for iPad, tuplets function like containers into which you can input notes of any duration, such as inputting a quarter note at the start of an eighth note tuplet.

When tuplets extend across barlines, Dorico for iPad automatically notates them correctly, such as a sextuplet appearing as two triplets. You can also allow tuplets to span barlines without division.

During tuplet input, tuplets are sticky, meaning that Dorico for iPad continues inputting notes as the specified tuplet until you stop tuplet input or note input.

You can show tuplets with different combinations of tuplet brackets and tuplet numbers/ratios. You can also show note symbols indicating the note value of the tuplet alongside tuplet numbers/ratios.

Video tutorial about tuplets (English)