Numbers that can be expressed in one or two words are generally spelled out, while other numbers are generally represented by numerals.
ten twenty-seven 394
A combination of words and numerals can be used for very large numbers.
Use words, not numbers, to begin a sentence.
Six students won scholarships.
Use numerals for the following:
money ($6.00) date (January 1, 2000)
time (3:00 p.m.) page (pages 10-20)
address (389 St. Clair) statistics (score was 7 to 2)