Data Representation

Question 1

Natural Number

Answer 1

a whole number that is used in counting

Question 2

Rational Number

Answer 2

any value that can be expressed as a ratio or fraction

Question 3

Irrational number

Answer 3

a number that cannot be expressed as a fraction and has an endless series of non-repeating digits.

Question 4

Ordinal numbers

Answer 4

describes the numerical position of objects

Question 5

Decimal (denary)

Answer 5

base 10 (uses digits 0 through 9)

Question 6

Hexadecimal

Answer 6

base 16 (uses digits 0-9 and letters A to F)

Question 7

Binary

Answer 7

base 2 (uses 0s and 1s)

Question 8

Why is the hexadecimal system used?

Answer 8

it is simple to represent a byte in just two digits, and fewer mistakes are likely to be made in writing a hex number than a string of binary digits

Question 9

Bit

Answer 9

the fundamental unit of information in the form of either a single 1 or 0

Question 10

Byte

Answer 10

a set of eight bits

Question 11

Nibble

Answer 11

a set of four bits

Question 12

ASCII code

Answer 12

uses 7 bits which form 128 different bit combinations. The first 32 codes represent non-printing characters used for control.

Question 13

Unicode

Answer 13

16-bit code - allowed more combinations and could represent alphabets from different languages

Question 14

Error checking

Answer 14

bits can change erroneously during transmission owing to interference. Computers use a variety of systems to verify that the data they receive is actually the same as the data that was sent.

Question 15

Parity bits

Answer 15

an additional bits that is used to check that the other bits transmitted are likely to be correct

Question 16

Checksums

Answer 16

a mathematical algorithm that is applied to a unit or packet of data. Algorithm is applied before and after transmission and if the two checksums match, the transmission is deemed successful.