## 1. The basics: important numbers in English and how to combine them to write out longer compound numbers.

### 1.1. What are the most important numerals and numbers in English?

- 1 = one (the lowest cardinal number; half of two;) Ex: one nation, one car, one piece of the mechanism.
**Idioms containing one:**at one = in a state of agreement; one and all = everyone; one by one = singly and successively; one for the road = a final alcoholic drink taken just before departing from a party (hopefully not drinking and driving).

- 2 = two (equivalent to the sum of one and one; one less than three;) Ex: two cars, two pieces of the mechanism. Not to be confused with: to, too.
**Idioms containing two:**in two = into two separate parts; put two and two together = draw a correct conclusion. - 3 = three (equivalent to the sum of one and two; one more than two;) Ex: three cars, three pieces of the mechanism. Not to be confused with: tree.
**Idioms containing three:**three sheets in the wind = intoxicated. - 4 = four (equivalent to the sum of two and two; one more than three;) Ex: four cars, four pieces of the mechanism. Not to be confused with: for, fore.
**Idioms containing four:**the four corners of the earth = the most distant or remote regions. - 5 = five (equivalent to the sum of two and three; one more than four;) Ex: five cars, five pieces of the mechanism.
**Idioms containing five:**take five = take a brief respite; give me five = shake hands with me. - 6 = six (equivalent to the sum of three and three; one more than five;) Ex: six cars, six pieces of the mechanism.
**Idioms containing six:**six feet under = dead and buried. - 7 = seven (equivalent to the sum of three and four; one more than six;) Ex: seven cars, seven pieces of the mechanism.
**Idioms containing seven:**at sixes and sevens = in disorder or confusion. - 8 = eight (equivalent to the sum of four and four; one more than seven;) Ex: eight cars, eight pieces of the mechanism.
**Idioms containing eight:**behind the eight ball (eightball) = in uncomfortable situation. - 9 = nine (equivalent to the sum of four and five; one more than eight;) Ex: nine cars, nine pieces of the mechanism.
**Idioms containing nine:**dressed to the nines = looking one's best. - 10 = ten (equivalent to the sum of five and five; one more than nine;) Ex: ten cars, ten pieces of the mechanism.
**Idioms containing ten:**count to ten = calm down.

- - - - - -
- 11 = eleven (one and ten)
- 12 = twelve (two and ten)
- 13 = thirteen (three and ten)
- 14 = fourteen (four and ten)
- 15 = fifteen (five and ten)
- 16 = sixteen (six and ten)
- 17 = seventeen (seven and ten)
- 18 = eighteen (eight and ten)
- 19 = nineteen (nine and ten)
- - - - - -
- 20 = twenty (two tens)
- 30 = thirty (three tens)
- 40 = forty (four tens)
- 50 = fifty (five tens)
- 60 = sixty (six tens)
- 70 = seventy (seven tens)
- 80 = eighty (eight tens)
- 90 = ninety (nine tens)
- - - - - -
- 100 = one hundred
- 200 = two hundred
- 300 = three hundred
- 400 = four hundred
- 500 = five hundred
- 600 = six hundred
- 700 = seven hundred
- 800 = eight hundred
- 900 = nine hundred
- - - - - -
- 1,000 = one thousand
- 10,000 = ten thousand
- 100,000 = one hundred thousand
- 1,000,000 = one million
- 10,000,000 = ten million
- 100,000,000 = one hundred million
- 1,000,000,000 = one billion
- 10,000,000,000 = ten billion
- 100,000,000,000 = one hundred billion
- 1,000,000,000,000 = one trillion, etc.

### 1.2. Combine the words in the list above to construct English words of longer compound numbers

**Let's see how to write out 65:**- 6 is in the tens place and 5 is in the ones place.
- 65 = 60 + 5 = six tens + five ones = sixty + five = sixty-five.
- Notice the hyphen (or the minus sign) between sixty and five.
**Let's see how to write out 1,765:**- 1 is in the thousands place, 7 is in the hundreds place, 6 is in the tens place and 5 is in the ones place.
- 1,765 = 1,000 + 700 + 60 + 5 = one thousands + seven hundreds + six tens + five ones = one thousand + seven hundred + sixty + five = one thousand seven hundred sixty-five.
- Notice the hyphen (or the minus sign) between sixty and five.

## 2. How to convert natural numbers (positive integers) to (US) American English words, how to write them out?

### 2.1. To know how to write a number in words it's important to know the place value of each digit.

- For example, the number 12,345 has a 1 in the ten thousands place, a 2 in the thousands place, a 3 in the hundreds place, a 4 in the tens place and a 5 in the ones place.
- 12,345 in words =
- = one ten thousands (10,000) + two thousands (2,000) + three hundreds (300) + four tens (40) + five ones
- = ten thousands (10,000) + two thousands (2,000) + three hundreds (300) + four tens (40) + five ones
- = ten thousand + two thousand + three hundred + forty + five
**= (ten + two) thousand + three hundred + forty-five**- = twelve thousand + three hundred + forty-five
- = twelve thousand three hundred forty-five.

### 2.2. Notes:

- 1: Note the hyphen (or the minus sign) in "thirty-four" above. Technically, it's correct to hyphenate all compound numbers from twenty-one (21) through ninety-nine (99).
- 2: In American English, when writing out natural numbers of three or more digits, the word "and" is not used after "hundred" or "thousand". So it is "one hundred twenty-three" and not "one hundred and twenty-three", though you may hear a lot of people using the last, informally.

In British English, the word "and" is used after "hundred" or "thousand" in numbers of three or more digits. - 3. Do not use commas when writing out numbers above 999: so it is "one thousand two hundred thirty-four" and not "one thousand, two hundred thirty-four". For clarity, use commas when writing figures of four or more digits: 1,234, 43,290,120, etc.

## 3. How to convert decimals to (US) American English words?

### To know how to write a decimal number in words it's important to know the place value of each digit, before and after the decimal point (decimal mark).

- This task is a little bit more complicated than converting an integer, because with a decimal number we have to worry also about the names of the places after the decimal point (decimal mark).
- Let's take an example: the decimal number 987.123456, made of numerals from 1 to 9. Notice that for this example's sake, every digit in this number is unique, so I can explain it better.

## 4. Steps to take in order to convert decimal numbers to (US) American English words.

### Step 1: What are the names of the places after the decimal mark:

- 1 is in the tenths place
- 2 is in the hundredths place
- 3 is in the thousandths place
- 4 is in the ten thousandths place
- 5 is in the hundred thousandths place
- 6 is in the millionths place;

### Step 2: How to spell out the number after the decimal mark, as an integer: 123,456?

- Using the explanations from the previous points above, 123,456 =
- = one hundred thousands (100,000) + two ten thousands (20,000) + three thousands (3,000) + four hundreds (400) + five tens (50) + six ones (6)
- = one hundred thousands + two ten thousands + three thousands + four hundreds + five tens + six
- = one hundred thousand + twenty thousand + three thousand + four hundred + fifty + six
**= (one hundred + twenty + three) thousand + four hundred + fifty + six**- = one hundred twenty-three thousand four hundred fifty-six.

### Step 3: What is the name of the smallest place (the place farthest to the right from the decimal mark)?

- In our number, it's the millionths place.

### Step 4: Spell out the whole number after the decimal, followed by the name of the smallest place:

- 0.123456 = one hundred twenty-three thousand four hundred fifty-six millionths;

### Step 5, final: Connect everything before and after the decimal mark with an "and":

- 987 = nine hundreds + eight tens + seven ones = nine hundred + eighty + seven = nine hundred eighty-seven;
- 987.123456 = nine hundred eighty-seven and one hundred twenty-three thousand four hundred fifty-six millionths.

## 5. When to write out numbers using words?

- Spell out all numbers beginning a sentence, "Forty years ago today,..." Not "40 years ago today,...".
- The Chicago Manual of Style calls for the numbers zero through one hundred to be written out - this would include forms like "one hundred million".
- Using words to write short numbers makes your writing look clean and classy. In handwriting, words are easy to read and hard to mistake for each other. Writing longer numbers as words isn't as useful, but it's good practice while you're learning.
- Otherwise, clarity should matter, for example when two numbers are used in a row: "They needed five 2-foot copper pipes to finish the job. ". "There were 15 six-foot tall men on the basketball team roster. ".
- Be consistent within a sentence. Do not write "... one million people..." but "... 1,000,000 cars...", stick to one or another, but not both.