Age

Rules for writing about age:

• Always use numbers.

• Hyphenate “year(s) old” only when used as a noun or an adjective. (examples: 5-year-old boy, the 4-year-old, she is 4 years old)

• When describing an age in decades, do not use an apostrophe. (example: people in their 30s)

• Use “ages” when describing the age range for events. (examples: for ages 6 and up, for ages
  6 to 9)

• Delete “ages” when it is not needed and implied by context. (examples: for children 6 and up, for adults 21 and older)