An Ordinal Number is a number that tells the position of something in a list, such as 1st, 2nd, 3rd, 4th, 5th, etc.
Ordinal numbers are important in multiple areas. The first use of ordinal numbers is to describe the order of objects, often written in the “figure” form. Another is to name exponents (e.g. 25 is “two to the fifth power”). Ordinal numbers are also used to name the denominators in fractions, often written in “full-word” form (e.g. one-third, three-fifths, six-tenths).
When ordinal numbers are written as figures the last two letters of the written ordinal are added to the cardinal number. Both the figure and the full-word formats are shown below.
The pattern established in the twenties continues for the rest of the numbers. These are called compound ordinals and only the last digit is written as an ordinal. For example, 345th is three hundred and forty-fifth.
Ordinal Numbers From 1st to 100th
[table id=1 /]
Ordinal Numbers – by Tens
|100||one hundred||one hundredth||100th|