Use numerals and am or pm, with a space in between. Don’t use minutes for on-the-hour time.

  • 7 am

  • 7:30 pm

Use a hyphen between times to indicate a time period

  • 7 am – 10:30 pm

Abbreviate decades when referring to those within the past 100 years.

  • the 00s
  • the 90s

When referring to decades more than 100 years ago, be more specific:

  • the 1900s
  • the 1890s

Do not use an apostrophe in these cases. “90s”, not “90’s”.