Mostly people search how to, correctly, write numbers within sentences. AP Style guide helps you to have an idea about the usage of numerals in publications.
This is a general rule that you should write numbers starting from one to nine by spelling them out. Otherwise, it is necessary to use figures after nine i.e. 10, 11, 12, and so on.
1. They need three more days for their presentation.
2. It is the third time that you are asking me about the extension.
3. There are almost 25 people inside the hall.
Rule for Addresses:
It is the rule that you should always use figures in your addresses. For example,
• 1200 California Ave. (Correct)
• Twelve hundred California Ave. (Wrong)
However, If you are referencing a number with street names, then you should capitalize and write full spellings from ‘First’ to ‘Ninth’. Otherwise, you have to use two-letter figures (i.e. 29th, 22nd, etc.)
• Go to Second St.
• Go to 12th St.
Rule for Ages:
If you are referring your age at any place, then you should use figures instead of spelling it out. For example,
• My brother is 20 years old.
• I always needed a six-year-old wild cat.
• She is in her 30s.
Rule for Dates:
While writing out dates, you should not use ordinal numbers. Always go with figures. For example, June 10.
Note: Avoid using figures like June 10th in writing dates.
Furthermore, you cannot use an apostrophe in references like 1900s or 1600s etc. However, an apostrophe is only needed in the references like ‘90s or ‘80s.
• The decade of the Gregorian calendar began in the 1900s.
• The ‘80s were the famous time because it was about peace and love.
Percentages need figures by dropping out its symbol (%). You should spell out the whole word ‘percent’. For example,
• She is donating more than 50 percent of her wealth.
Rule for Dimensions:
You should use figures while writing out dimensions. For example,
• My height is about 5 feet 5 inches.
• The 10-by-10 curtain.
• This room is 30 yards in length.
• You should be at least 150 pounds in weight.
Rule for Highway Destinations
Use figures while writing about highways. For example,
• You should choose route 66 to reach early.
• There was a very bad traffic on interstate 5.
Rule for Millions/Billions/Trillions or Money:
Use only figures. For example,
• There were almost 1 million people outside the court.
• Will you donate $10 billion?
• It costs only 4 cents.
• I will pay $20 for that purse.
Rule for Speed:
Only figures needed. For example,
• Santa Ana winds could gust up to 60 mph in some Southern California areas. (LA Daily News)
Rule for Time:
You should use figures for time. However, you should spell out noon and midnight. For example,
• 10 p.m.
• 5:15 a.m.
• 6 0’clock
Rule for Temperature
Only use figures. For example,
• It was minus 8 yesterday morning.
• You can’t go out, it’s 50 degrees outside.
Note: Don’t use figure for 0. You should spell it out (as zero).
Rule for Expressions or Quotations
You should spell out the numbers within quotations or expressions. For example,
• One day, you will come to know about my importance.
• A thousand splendid suns.
• You can ask questions one by one.
Spell out at the beginning of a sentence:
You should spell out the number at the beginning of a sentence. For example,
• Five hundred pages have been ruined.
Note: In case of years, you should use figures. For example, 1991 is my birth year.
I hope that from the above explanation, you are now clear with AP Style numbers. Memorize the rules and stop getting trouble any more.