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”.