I've always learned that the difference between 'number' and 'numeral' was that number is the idea and numeral is the representation. But after a discussion with @terdon in chat, I'm not so sure anymore. Different sources say different things.
Like, Merriam Webster defines numeral as:
a conventional symbol that represents a number
But lists 'number' as a synonym.
And in their number entry:
a word, symbol, letter, or combination of symbols representing a number (definition 4)
The top Google result says:
A numeral is a symbol or name that stands for a number. Examples: 3, 49 and twelve are all numerals. So the number is an idea, the numeral is how we write it.
So what is the difference between 'number' and 'numeral'?
Best Answer
Merriam Webster's Thesaurus entry for "numeral" lists "number" and "numeral" as synonyms. This is due to the fourth definition for "number", which provides a definition for "number" that is synonymous with the definition for "numeral".
For comparison, here is the same dictionary's definition for "numeral":
Where the need arises to distinguish between the mathematical value represented by a group of symbols and the symbols themselves, "number" is the preferred word to describe the abstracted mathematical value that is being represented, and "numeral" is the preferred word to describe the group of symbols representing the number. In other words, "numeral" is what you call the symbol or groups of symbols that represents a "number". This distinction isn't particularly useful in everyday correspondence because it's rare that the need arises to consider the characters that make up a number. As an example, 119 is a numeral, and the number it represents can be represented more elaborately or verbosely using various mathematical definitions, such as ((1 * 10^2) + (1 * 10) + 9).