Number Notation: Number Name How Many
Number Notation: Number Name How Many
Number Notation: Number Name How Many
Name
zero
How many
one
two
three
four
five
six
seven
eight
nine
10
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
Number
Name
How Many
100
one hundred
ten tens
1,000
one thousand
ten hundreds
10,000
ten thousand
ten thousands
100,000
1,000,000
one million
Some people use a comma to mark every 3 digits. It just keeps track of the digits
and makes the numbers easier to read.
Beyond a million, the names of the numbers differ depending where you live. The
places are grouped by thousands in America and France, by the millions in Great
Britain and Germany.
Name
American-French
English-German
million
1,000,000
1,000,000
billion
1,000,000,000 (a thousand
millions)
1,000,000,000,000 (a million
millions)
trillion
1 with 12 zeros
1 with 18 zeros
1 with 24 zeros
1 with 30 zeros
sextillion
1 with 21 zeros
1 with 36 zeros
septillion
1 with 24 zeros
1 with 42 zeros
octillion
1 with 27 zeros
1 with 48 zeros
googol
googolplex
Fractions
Digits to the right of the decimal point represent the fractional part of the decimal
number. Each place value has a value that is one tenth the value to the immediate
left of it.
Number
Name
Fraction
.1
tenth
1/10
.01
hundredth
.001
thousandth
.0001
ten thousandth
1/10000
.00001
hundred thousandth
1/100000
1/100
1/1000
Examples:
0.234 = 234/1000 (said - point 2 3 4, or 234 thousandths, or two hundred thirty
four thousandths)
4.83 = 4 83/100 (said - 4 point 8 3, or 4 and 83 hundredths)
SI Prefixes
Number
10 1
10 2
10 3
10 6
10 9
10 12
10 15
10 18
10 21
10 24
Prefix
dekahectokilomegagigaterapetaexazetayotta-
Symbol
da
h
k
M
G
T
P
E
Z
Y
Number
10 -1
10 -2
10 -3
10 -6
10 -9
10 -12
10 -15
10 -18
10 -21
10 -24
Prefix
decicentimillimicronanopicofemtoattozeptoyocto-
Symbol
d
c
m
u (greek mu)
n
p
f
a
z
y
Roman Numerals
I=1
V=5
_
V=5,000
X=10
_
X=10,000
L=50
_
L=50,000
C=100
_
C = 100 000
D=500
_
D=500,000
M=1,000
_
M=1,000,000
1 = I
2 = II
3 = III
4 = IV
5 = V
6 = VI
7 = VII
8 = VIII
9 = IX
10 = X
11 = XI
12 = XII
13 = XIII
14 = XIV
15 = XV
16 = XVI
17 = XVII
18 = XVIII
19 = XIX
20 = XX
21 = XXI
25 = XXV
30 = XXX
40 = XL
49 = XLIX
50 = L
51 = LI
60 = LX
70 = LXX
80 = LXXX
90 = XC
99 = XCIX
Binary(2)
Ternary(3)
Octal(8)
Hexadecimal(16)
10
11
10
100
11
101
12
110
20
111
21
1000
22
10
1001
100
11
10
1010
101
12
11
1011
102
13
12
1100
110
14
13
1101
111
15
14
1110
112
16
15
1111
120
17
16
10000
121
20
10
17
10001
122
21
11
18
10010
200
22
12
19
10011
201
23
13
20
10100
202
24
14
Each digit can only count up to the value of one less than the base. In hexadecimal,
the letters A - F are used to represent the digits 10 - 15, so they would only use
one character.