Fundamentals of data representation

natural number

a positive whole number including 0

integer

All whole numbers (both positive and negative) and zero.

rational number

Any number that can be expressed as a ratio of integers

irrational number

a number that can NOT be expressed as a ratio of two integers or as a repeating or terminating decimal - Pi or any square root of an imperfect square are considered irrational

real number

any positive or negative number with or without a fractional part

ordinal number

A whole number that names the position of an object in sequence ( first, second, third...)

cardinal numbers

A number that identifies the size of something.

well-ordered set

A group of related numbers with a defined order.

array

a data structure where data items are grouped together under single identifier and are the accessed based on their position

Number bases

the number of different digits available within a particular number system e.g. binary - base 2

bit

A single binary digit: 1 or 0

Byte

A group of eight bits used to represent a singe character

unit

the grouping together of bits or bytes to form larger blocks of measurements e.g. GB, MB

Hexadecimal

A base-16 number system that uses sixteen distinct symbols 0-9 and A-F to represent numbers from 0 to 15.

unsigned binary

Binary that represents positive numbers only

two's complement

A method of working with signed binary values where when the binary value is 1 you change the rest of them to their opposing value until the most significant bit then do -128 plus all of the binary digits that are 1.

fixed point

Where the decimal/binary point is fixed within a number

floating point

Where the decimal/binary point can move within a number

Signed binary

Binary with a positive or negative sign

overflow

When a number is too large to be represented with the number of bits allocated

underflow

When a number is too small to be represented with the number of bits allocated.

normalisation

A process for adjusting numbers onto a common scale

precision

how accurate a number is

mantissa

The significant digits that make up a number

exponent

the 'power of' part of a number indicating how far a binary point should be shifted left or right.