Cardinal and ordinal numbers

Before a noun, we use ordinal (e.g. first, second, tenth) numbers; after a noun, we use cardinal (e.g. one, two, ten) numbers.

The fourth chapter OR Chapter Four

The fifth act OR Act Five

The names of kings and queens are said with ordinal numbers.

Henry VIII: Henry the Eighth (NOT Henry Eight)

Louis XIV: Louis the Fourteenth (NOT Louis Fourteen)

Names of centuries

The period from 1501 – 1600 is called the 16^th century (NOT the 15^th century)

The period from 1801 – 1900 is called the 19^th century (NOT the 18^th century)

Floors

When it comes to floors, there is usually a difference between British and American usage. The ground floor of a British house if the first floor of an American house; the first floor of a British house is the second floor of an American house.

Use of and

In British English, and is used before the tens in a number. In American English, and can be dropped.

546 – Five hundred and forty-six (British English)

610 – Six hundred ten / Six hundred and ten (American English)

6,376 – Six thousand three hundred and seventy-six (British English)

In writing we generally use commas to divide large numbers into groups of three figures. Commas can be left out in four-figure numbers.

4,376 OR 4376 (NOT 4.376)

2,867,512 (NOT 2867512)