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11 - Hexadecimal

 1. What is Hexadecimal?

  A mayan number system that is no longer in use today but has been referred to in star wars

  A number system comprised of 16 symbols: 0 - 9 and A - F

  A language that is comprised of hex (which means six in latin) symbols, 0 - 2 and A, B and C

  A number system that has 'hexagonal' shaped symbols in it\

 2. Why is Hexadecial useful?

  All of the above

  For e.g. to represent 255 in binary you would need 8 bits 11111111 but in Hex that would take just two digits FF

  It has a much shorter way of representing a byte of data (8 bits)

  It is more readable (to humans) than Binary

 3. Using the table below, 3 in Decimal is what in Hexaadecimal?
Hexadecimal corresponding to Denary
====================================
Denary 0   1   2   3   4   5   6   7   8  9  10   11  12   13  14   15  

Hex    0   1   2   3   4   5   6   7   8  9   A   B    C   D    E   F

  4

  2

  1

  3

 4. Using this table, 'A' in Hexadecimal is what in Decimal?
Hexadecimal corresponding to Denary
====================================
Denary 0   1   2   3   4   5   6   7   8  9  10   11  12   13  14   15  

Hex    0   1   2   3   4   5   6   7   8  9   A   B    C   D    E   F

  B

  11

  13

  10

 5. 16 in Hex is what in Decimal? Point out the error in the calculation below.
Denary to Hexadecimal
====================================
#1 Step 1 - Take the Dec number and convert it into Binary

16 = 

128  64  32  16   8  4  2  1
==============================
0    0   0   1    0  0  0  0

#2 Step 2 - Divide the bits into groups of four

0001     and  0000

#3 Convert each group of four back .....

8 4 2 1      8 4 2 1
-------      -------             
0 0 0 1       0 0 0 0

= 1       and   0

  16 in Hex is 21 in Decimal

  16 in Hex cannot be represented in Decimal as the numbers stop at 15

  16 in Hex is 'G' in Decimal

  There are no errors. 16 in Decimal is 10 in Hex

 6. 21 in Decimal is ……..? Is the calculation below correct?
Convert a Decimal number into Hex
====================================
#1 Step 1 - Take the number and convert it into binary

21 = 

128  64  32  16   8  4  2  1
==============================
0    0   0   1    0  1  0  1

#2 Step 2 - Divide the bits into groups of four

0001     and  0101

#3 Convert each group of four back...

8 4 2 1      8 4 2 1
-------      -------             
0 0 0 1      0 1 0 0

= 1       and  4

  It is correct. 21 in Decimal is 14 in Hex

  The first group of four bits should have been 1000, so the final answer should have been 84 in Hex

  None of the above

  The second group of four bits should have been 0101 which is 5, so 21 in Decimal is 15 in Hex

 7. 1A in Hex is 26 in Decimal - True or False?

  FALSE

  TRUE

 8. What is 1E (Hex) in Decimal?

  30

  20

  40

  50

 9. What is 18 (in Hex) in Decimal?

  24

  34

  23

  12

 10. 20 in Decimal is what in Hex?

  15

  14

  16

  17

 11. What is E3 (in hex) as a Binary number?

  11100000

  11100011

  101

  11101010

 12. What is D1F (in hex) as a Binary number?

  111111111

  23423434

  110010

  1.101E+11

 13. Hexadecimal numbers are often used to represent colours within HTML or CSS.

  FALSE

  TRUE

 14. By changing the intensities of red, green and blue, we can create almost any colour. Fill in the blanks
E.g. orange can be represented as #FFA500, which is 
(________ red, 165 green, 0 blue)

  333

  32

  255

  256

 15. A Media Access Control (MAC) address is a number which uniquely identifies a device on the internet. Is this Hex?
e.g. D5-BE-E9-8D-44-9C

Expressing MAC addresses in hexadecimal format makes 
them easier to read and work with.

  True

  False