Collective nouns—such as family, team, audience, group, jury, crowd, band, class, and committee—and fractions can take either singular or plural verbs, depending on whether they refer to the group as a single unit or to the multiple members of the group. The meaning of a sentence as a whole is your guide.

The jury acts as a single unit.

The members of the jury act as multiple individuals.

Two-thirds refers to the single portion of the park that burned.

One-third here refers to the students who commuted as individuals.

Treat phrases starting with the number of as singular and with a number of as plural.