Spell It Out

Spell out numbers one through nine.

I have five brothers and three sisters.
I bought two pizzas.
Only nine people came to the meeting.

Use numerals for numbers 10 and above.

I have 10 cousins.
I bought a package of 30 paper cups.
More than 30,000 people went to the concert.

Spell out numbers that start a sentence.

Nineteen niney-nine was a good year.
Two students were caught shoplifting.
Ten thousand people were hurt in the earthquake.

• (I'll add more to this list as time goes on.)

References:

• US
• The Chicago Manual of Style by University of Chicago Press Staff
  

• Japan
• The Chicago Manual of Style by University of Chicago Press Staff
  

• United States Government Printing Office Style Manual 2000, Chapter 12. Numberals, Section 12.4.
• USGPO Style Manual