math.com
Home    |    Teacher    |    Parents    |    Glossary    |    About Us
Homework Help Practice Ask An Expert Calculators & Tools Games Store
Email this page to a friend Email this page to a friend
Resources
· Cool Tools
· Formulas & Tables
· References
· Test Preparation
· Study Tips
· Wonders of Math
 
Search


  
Number Notation
(Math | General | Number Notation)

 

Names | SI (Metric) Prefixes | Roman Numerals | Bases

Hierarchy of Decimal Numbers

Number
Name
How many
0 zero  
1 one
2 two
3 three
4 four
5 five
6 six
7 seven
8 eight
9 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 one hundred thousand one hundred thousands
1,000,000 one million one thousand thousands

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, and also the context. The places are grouped by thousands in countries using the "short scale" (such as the United States, Australia and English-speaking Canada), and by the millions in countries using the "long scale" (such as France and Germany). For further details on usage by country, see this article.

Name Short scale Long scale
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
quadrillion 1 with 15 zeros 1 with 24 zeros
quintillion 1 with 18 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
1 with 100 zeros
googolplex
1 with a googol of zeros

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

1/100

.001 thousandth

1/1000

.0001 ten thousandth 1/10000
.00001 hundred thousandth 1/100000

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 Prefix Symbol
10 1 deka- da
10 2 hecto- h
10 3 kilo- k
10 6 mega- M
10 9 giga- G
10 12 tera- T
10 15 peta- P
10 18 exa- E
10 21 zeta- Z
10 24 yotta- Y
Number Prefix Symbol
10 -1 deci- d
10 -2 centi- c
10 -3 milli- m
10 -6 micro- u (greek mu)
10 -9 nano- n
10 -12 pico- p
10 -15 femto- f
10 -18 atto- a
10 -21 zepto- z
10 -24 yocto- y

 

Roman Numerals

I=1   (I with a bar is not used)
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

Roman Numeral Calculator

Examples:

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

There is no zero in the roman numeral system.

The numbers are built starting from the largest number on the left, and adding smaller numbers to the right. All the numerals are then added together.

The exception is the subtracted numerals, if a numeral is before a larger numeral, you subtract the first numeral from the second. That is, IX is 10 - 1= 9.

This only works for one small numeral before one larger numeral - for example, IIX is not 8, it is not a recognized roman numeral.

There is no place value in this system - the number III is 3, not 111.

Number Base Systems
Decimal(10)
Binary(2)
Ternary(3)
Octal(8)
Hexadecimal(16)

0

0
0

0

0

1
1
1
1
1
2
10
2
2
2
3
11
10
3
3
4
100
11
4
4
5
101
12
5
5
6
110
20
6
6
7
111
21
7
7
8
1000
22
10
8
9
1001
100
11
9
10
1010
101
12
A
11
1011
102
13
B
12
1100
110
14
C
13
1101
111
15
D
14
1110
112
16
E
15
1111
120
17
F
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.

Java Base Conversion Calculator

  
 
  

 
Contact us | Advertising & Sponsorship | Partnership | Link to us

© 2000-2023 Math.com. All rights reserved.     Legal Notices.     Please read our Privacy Policy.