To start with, numerals are those symbols which represent a number. Numerals also include words.
There are a wide array of rules and exceptions about writing numbers in sentences, but most of the times it depends on the writing style i.e. it is only about the style whether you want to use numerals or spell out a number. The general rule which is globally accepted is that words should be used for numbers from one to nine, but the rules related to numbers above that change from style to style.
Another rule suggests that words should be used for numbers from one to hundred, one to ten and any other combination of numbers which can be written with two or more words.
Normally, people who write business or other procedural documents tend to use numerals. On the other hand people who don’t write technical documents tend to write the words for the numbers. Apart from this there are many other ways to writing numbers in sentences, but the gist of it all is to choose a writing style and stick to it.
Following are some guidelines on writing numbers in sentences which are universally accepted.
• Numbers that are next to each other
In this case, when you are writing numbers that are next to each other, write words for one of them and a numeral for the other. This makes reading a lot easier. Here is an example:
“We used 62 eleven-inch pencils”
Either you right 62 in numerals, and 11-inches in words or you could write 62 in words and 11-inches in numerals.
• Starting of a Sentence
When you use a number at the starting of a sentence, most guidelines suggest writing them in words. In case where the number is exceptionally long and you write them in words, then you should put the sentence in another way so that the numbers don’t come in the beginning of the sentence. For example the following sentence would be very difficult to understand, if it was written in numbers.
Thirty thousand nine hundred sixty five people gathered at the conference. It would be better to put this sentence in an entirely different way for easier comprehension.
The conference was attended by 30,965 people.
In the second example, the concept of passive voice has been introduced, which has made the comprehension easier. According to some style guides an exception is made i.e. when you are using a year at the starting of a sentence then a numeral can be used. But most of the style guides urge to use words in place of numerals.
• Writing numbers in Dialogues
The rules related to writing numbers in dialogues are very clear-cut. While writing a dialogue, for instance when mentioning someone in a article or writing dialogues in a creative writing; you need to spell out the numbers.
This is not all about writing numbers in sentences. There are wide variety of rules and exceptions to it. A study guide would be preferable to cover all the grounds of writing numbers in sentences.