Rules for writers, Tenth edition - Diana Hacker, Nancy Sommers 2021

Treat collective nouns as singular unless the meaning is clearly plural
Make subjects and verbs agree
Grammar

Collective nouns such as jury, committee, audience, crowd, troop, family, and couple name a class or a group. Collective nouns are nearly always treated as singular to emphasize the group as a unit. Occasionally, when there is some reason to draw attention to the individual members of the group, a collective noun may be treated as plural. (See also 22b.)

To underscore the notion of individuality in the second sentence, many writers would add a clearly plural noun.

NOTE: The phrase the number is treated as singular, a number as plural.

NOTE: In general, when a fraction or a unit of measurement is used with a singular noun, treat it as singular; when it is used with a plural noun, treat it as plural.