Numbers

Special Number Expressions

Zero

The number 0 has different names depending on the context:

• zero → the number itself, temperatures, science
  It was ten degrees below zero.
• nil → sports results
  The match ended five to nil.
• nought → calculations (mainly British English)
  Six minus six is nought.
• oh → telephone numbers and codes, when reading digits separately
  My phone number is six-one-six-two-three-oh.
• love → tennis scores only
  Fifteen–love.

Fractions

Fractions are usually made with a cardinal number + fraction word. Fraction words are usually the same as ordinal numbers (one third, three fifths) but some of them are special: a half and a quarter. For example:

• 1/3 → one third
• 5/6 → five sixths
• 7/3 → seven thirds
• 1/2 → one half (also: a half)
• 1/4 → a quarter
• 3/4 → three quarters

When the top number is more than one, the fraction word is usually plural:

• 2/2 → two halves
• 3/4 → three quarters

Whole numbers and fractions are joined with and:

• 6 3/4 → six and three quarters
• 11 1/6 → eleven and a sixth

Decimals

Numbers with a dot are called decimal numbers. The dot is called the decimal point.

• We read the digits after the decimal point separately:
  4.32 → four point three two
• Decimals can also be expressed as fractions:
  4.29 → four and twenty-nine hundredths

Decades and ages

Cardinal numbers can be used as plural nouns when talking about decades and approximate ages.

• This music was popular in the eighties.
• He is in his seventies.
• Kate is in her twenties.

Quick reference

• zero → general number, temperatures, science
  nil → sports
  oh → phone numbers and codes
• fractions → number + fraction word
  one third, three quarters, one half
• decimals → read digits after the point separately
  4.32 → four point three two
• decades and ages → plural numbers
  the eighties, in his seventies

Ordinal Numbers

Ordinal numbers (first, second, third) tell us the position or order of something. We also use them in dates, centuries, and fractions.

• He lives on the third floor.
• It was my first accident.
• Jim was fifth in the competition.
• It's the eleventh of January. (dates, also written as: January 11th)
• There was a lot of poverty during the nineteenth century. (centuries)
• Use two thirds of a cup of milk. (fractions)

Forming ordinal numbers

The first three have special irregular forms:

• one → first (or 1st)
• two → second (or 2nd)
• three → third (or 3rd)

But most ordinal numbers are formed by adding -th to the cardinal number.

• four → fourth
• seven → seventh
• ten → tenth
• eleven → eleventh
• thirteen → thirteenth
• nineteen → nineteenth
• a hundred → hundredth
• a thousand → thousandth

Some have an irregular spelling:

For large compound numbers above twenty, only the last part changes into an ordinal number.

• Numbers ending in 1 → first (-st)
  21 → twenty-first (21st)
• Numbers ending in 2 → second (-nd)
  32 → thirty-second (32nd)
• Numbers ending in 3 → third (-rd)
  43 → forty-third (43rd)
• Most other numbers → -th
  45 → forty-fifth (45th)
  250 → two hundred and fiftieth (250th)

Watch out: 11, 12 and 13 always end in -th: 11th, 12th, 13th.

Quick reference

• cardinal numbers → one, two, three = how many
• ordinal numbers → first, second, third = position or order
• first, second, third
• fourth, fifth, eighth
• eleventh, twelfth, fifteenth
• twentieth, twenty-first, twenty-fifth