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. 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
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.
source:math.com