Numbers are generally used for specifying amounts and in mathematics: addition, subtraction, multiplication, and division. You have undoubtedly encountered them in many forms. Let’s first review cardinal numbers:
| 0 | zero | 21 | twenty-one |
| 1 | one | 22 | twenty-two |
| 2 | two | 30 | thirty |
| 3 | three | 40 | forty |
| 4 | four | 50 | fifty |
| 5 | five | 60 | sixty |
| 6 | six | 70 | seventy |
| 7 | seven | 80 | eighty |
| 8 | eight | 90 | ninety |
| 9 | nine | 100 | one hundred |
| 10 | ten | 101 | one hundred one |
| 11 | eleven | 102 | one hundred two |
| 12 | twelve | 200 | two hundred |
| 13 | thirteen | 500 | five hundred |
| 14 | fourteen | 1,000 | one thousand |
| 15 | fifteen | 2,000 | two thousand |
| 16 | sixteen | 10,000 | ten thousand |
| 17 | seventeen | 11,000 | eleven thousand |
| 18 | eighteen | 20,000 | twenty thousand |
| 19 | nineteen | 100,000 | one hundred thousand |
| 20 | twenty | 111,111 | one hundred eleven thousand one hundred eleven |
Careful! English names for certain large numbers differ from those in other languages:
| English | Number |
| million | 1,000,000 |
| billion | 1,000,000,000 |
| trillion | 1,000,000,000,000 |
When numbers are used in equations, there are specific mathematical terms to be used. In addition, numbers are combined by either the word plus or the word and: five plus three, ten and nine.
- In subtraction, the equation requires using the word minus (–): ten minus four.
- In multiplication, the equation requires using the word times (×): six times three.
- In division, the equation requires the phrase divided by (÷ or /): twenty divided by five.
- If an equation has an equal sign (=) in it, it is stated as equals or is: two plus two equals four, six minus three is three.
- If a number is a decimal, the decimal is expressed by the word point: 6.5 is said as “six point five”; 10.7 is said as “ten point seven.”
The ordinal numbers are those that show a rank in a group or series. Most ordinals are formed by adding -th to the end of the number: tenth, twentieth, sixty-seventh, hundredth, and so on. But five ordinal numbers have special spellings which should be memorized:
- 1 = first
- 2 = second
- 3 = third
- 5 = fifth
- 12 = twelfth
Some example sentences with ordinal numbers:
- We have three daughters, but Denise was our first.
- The second seating for dinner is at 8:30 P.M.
- She was born on the twenty-fifth of June.
Dates are expressed in two ways: May fifth or the fifth of May. When giving a date as a number, it is most common to give the month before the day: 9/11 = September eleventh, 6/12 = June twelfth. In many other languages, the day precedes the month. This can cause confusion, because to some people 6/12 means “the sixth of December.” To English speakers it most commonly means “June twelfth.” To avoid such confusion, it is wise to give dates in this form: June 12, 2005.
Ordinals are also used to express fractions other than ½:
- ½ = one-half (not an ordinal)
- ¼ = one-fourth (Note: One-fourth is sometimes expressed as “one-quarter” or “a quarter.”)
- ⅓ = one-third
- 3/10 = three-tenths
- 14/25 = fourteen twenty-fifths (Notice the plural formation of the ordinal when the accompanying number is greater than one.)
Years that precede 2000 are expressed in two parts: 1850 is said as “eighteen fifty,”
1066 is said as “ten sixty-six.” The years that follow 1999 are said another way:
| 2000 | two thousand |
| 2001 | two thousand one, or twenty oh one |
| 2002 | two thousand two, or twenty oh two |
| 2010 | two thousand ten, or twenty ten |
| 2022 | two thousand twenty-two, or twenty twenty-two |
When saying on what date an event occurred, the word on is optional:
- The boy was born on May first.
- The boy was born May first.