ordinal numbers: Setyembre 2011

When objects are placed in order, we use ordinal numbers to tell their position. Ordinal numbers are similar to the numbers that you learned before (they are called Cardinal numbers). If ten students ran a race, we would say that the student that ran the fastest was in first place, the next student was in second place, and so on.

The first ten ordinal numbers are:

First

Second

Third

Fourth

Fifth

Sixth

Seventh

Eighth

Ninth

Tenth

Table of Ordinal Numbers

Ordinal Numbers from 1 through 1,000,000
1	st	first	11	th	eleventh	21	st	twenty-first			31	st	thirty-first
2	nd	second	12	th	twelfth	22	nd	twenty-second			40	th	fortieth
3	rd	third	13	th	thirteenth	23	rd	twenty-third			50	th	fiftieth
4	th	fourth	14	th	fourteenth	24	th	twenty-fourth			60	th	sixtieth
5	th	fifth	15	th	fifteenth	25	th	twenty-fifth			70	th	seventieth
6	th	sixth	16	th	sixteenth	26	th	twenty-sixth			80	th	eightieth
7	th	seventh	17	th	seventeenth	27	th	twenty-seventh			90	th	ninetieth
8	th	eighth	18	th	eighteenth	28	th	twenty-eighth			100	th	one hundredth
9	th	ninth	19	th	nineteenth	29	th	twenty-ninth		1,000		th	one thousandth
10	th	tenth	20	th	twentieth	30	th	thirtieth	1,000,000			th	one millionth

Form

Spelling of Ordinal Numbers

Just add th to the cardinal number:

four - fourth
eleven - eleventh

Exceptions:

one - first
two - second
three - third
five - fifth
eight - eighth
nine - ninth
twelve - twelfth

In compound ordinal numbers, note that only the last figure is written as an ordinal number:

421st = four hundred and twenty-first
5,111th = five thousand, one hundred and eleventh

Figures

When expressed as figures, the last two letters of the written word are added to the ordinal number:

first = 1st
second = 2nd
third = 3rd
fourth = 4th
twenty-sixth = 26th
hundred and first = 101st

Math Lessons by Grade

Kindergarten	First	Second	Third	Fourth
Fifth	Sixth	Seventh	Eighth

Math Topics

Addition	Algebra	Comparing	Counting	Decimals
Division	Equations	Estimation	Exponents	Fractions
Geometry	Graphs	Measurement	Mental Math	Money
Multiplication	Naming Numbers	Patterns	Percent	Place Value
Practical Math	Properties	Ratios	Statistics	Subtraction