Numbers

How numbers are written can vary from language to language and even from institution to institution within a single language. To ensure a polished and consistent finished product, it is thus important to apply the same rules throughout a given text. With this goal in mind, the UOC has put together the following guidelines.

As a general rule, in running text, spell out the numbers one to nine, but use figures for numbers 10 and up. Examples:


This notwithstanding, when a passage contains both, try to be consistent. For instance, if a number in a given category must be written in figures, use figures for all the numbers in that category. Examples:


Such exceptions should be applied in the passage in question but need not extend to the text as a whole.

Exceptions are also made for times and dates, which, even in running text, are nearly always referred to with figures. Examples:


Remember, both cardinal and ordinal compound numbers from 21 to 99 take hyphens when written as words. Examples:


In non-technical texts, use words when there is no way to avoid beginning a sentence with a number. Example:


That said, another solution can often be found. Example:


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In general, try not to combine single-digit figures with words in hyphenated expressions. Example:


In contrast, multi-digit figures and words are sometimes combined in hyphenated expressions, particularly in certain set phrases. Examples:


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When two numbers appear next to each other, do not express both as figures or both as words. Instead express one as a figure and the other as a word to prevent confusion. Either order is acceptable, but be sure to be consistent throughout the text. Example:


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Use figures to refer to specific numbers, but write round or approximate numbers as words. Compare:


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Hundreds and thousands may be expressed entirely in figures or entirely in words, but not in a mixture of both. Examples:


In contrast, the words million, billion and trillion may be used with figures or words. That said, when the number is not an integer or is greater than 9, figures are preferred. Examples:


Finally, unlike Catalan, AmE and, increasingly, BrE use the short-scale system for naming large numbers. Under this system, the term billion refers to 1x109 (1,000,000,000), whereas trillion is used for 1x1012 (1,000,000,000,000). To ensure consistency in its English-language texts, the UOC recommends using the 'short billion' to express 1x109 unless otherwise explicitly instructed. Example:


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In general, write fractions as words. The words should be hyphenated when used as adjectives or adverbs, but not when used as nouns. Examples:


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Write numbers as words when they are used with the words per cent (e.g. fifteen per cent). In contrast, write them as figures when using the symbol (e.g. 15%).

Note that while BrE uses the spelling per cent, in AmE this term is written as a single word (percent).


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Unlike in Catalan, when writing figures in English use points to indicate decimals and commas to indicate thousands, millions, etc. Examples:


Notwithstanding the above, as in Catalan, commas should not be used to indicate thousands in years (e.g. 14 July 1790), page numbers (e.g. pp 1743–1749) or street numbers (e.g. 1500 Main Street). 

Please note that the terms billion and trillion can also have different meanings in English and Catalan.


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Use figures with abbreviations and symbols of measurement and monetary units. Examples:


Note, however, that when the units are spelled out, the number may be written with figures or letters (e.g. 7 kilograms or seven kilograms). The opposite is not true (e.g. 7 kg not seven kg).


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Use figures in lists of objects, ingredients, tallies, etc., when they are written out in list format. Example:


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Use figures when referring to ranges denoted by an en-dash, but not necessarily ranges denoted with words. Compare:


Remember to be consistent when describing ranges. If you begin with between, continue with and; if you begin with from, continue with to; do not combine a preposition with a dash; etc. Examples:


When using words to connect the two extremes of a range, repeat any symbols or multiples. Examples:


In contrast, if you use an en-dash to indicate a range, repeat only those symbols and/or multiples that change. In such cases, change the closed en-dash to an open one. Compare:


Finally, one good rule of thumb when writing ranges is to repeat symbols that are joined to the end of a numeral but not those that are separated by a space. For instance:


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Use figures when citing serial numbers, such as those used to identify the different sections of a treaty or law. Example:


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Write numbers as figures when citing statistics. Example:


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Use figures for all numbers in tables and graphs. Example:


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Use figures when citing vote tallies. Example:


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Dates should be written as follows: the number of the day, followed by the name of the month written in full, followed by a four-digit year. There should be no internal punctuation. Examples:


Where space is absolutely of the essence, use figures separated by slashes (e.g. 1/1/2018). However, wherever possible, write out the name of the month to prevent confusion between BrE and AmE formats.

When a date is preceded by the day of the week, in BrE, do not separate them with a comma. Example:


Please note that in AmE, this same date would be written:


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When referring to a year in running text, use all four digits for added clarity (e.g. 2001, not '01). There is no need to repeat the year when it is already clear from context.

In English, decades can be expressed in words (e.g. the sixties) or figures (e.g. the '60s, the 1960s). In order to prevent confusion stemming from the most recent turn of century, the UOC prefers to use four-digit figures.


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When citing times, use a 12-hour clock followed by a space and the abbreviation a.m. or p.m. (lowercased with full stops). It is UOC style to separate the hours and minutes with a full stop. Examples:


Note that in AmE, it is more common to separate the hours and minutes with a colon (5:30 p.m.).

For added clarity, consider using 12 noon (instead of 12 p.m.) and 12 midnight (instead of 12 a.m.), where possible.

Remember, unlike in Catalan, the abbreviation h is not used to indicate specific times, just duration. Examples:


As with other ranges, when indicating time spans, be sure to use the right collocation. In other words, use from with to (e.g. from June to September), between with and (e.g. between 1954 and 1957), or a single closed-up en-dash without any preposition at all (e.g. Monday–Friday).

When indicating a span of years with a closed-up en-dash, do not repeat the century in the second year unless it changes. Exceptions may be made for the first decade of a century. Examples:


The UOC recommends using either of the following formats to refer to academic years: the academic year + XXXX-XXXX(where XXXX is a four-digit reference to a specific calendar year) or the + XXXX-XXXX+ academic year. Thus:


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Unlike in Catalan, in English centuries are generally denoted with Arabic ordinal numbers, rather than Roman numerals. Compare:


Similarly, in English, unlike in Catalan, Arabic ordinal numbers, rather than Roman numerals, are generally used to indicate the edition of an event. Thus:


In contrast, Roman numerals are used in English to indicate the level or sequence of courses with the same name. Example:


They are also used in the names of monarchs and certain high-ranking religious figures such as popes and Orthodox patriarchs. Examples:


Finally, the names of the first and second world wars are also generally written and abbreviated with Roman numerals. Thus:


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