Friday 25 May 2012

tech. English

Units 13,15,16,17,18,19,22,23,27 answers :http://www.mediafire.com/?n96k6f9jq6r08h0
unit 14 answer : http://www.mediafire.com/?pffe74cs31xee6p

Tuesday 1 May 2012

Monday 9 January 2012

num system

Numbering systems

Decimal: {0, 1, 2, 3, 4, 5…}

Binary: {0, 1}

Octal: {0, 1, 2, 3, 4, 5, 6, 7}

Hexadecimal: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F}

Conversion methods

  • From decimal to binary (divide the decimal number by 2 then take the remainder –up right-to be the binary representation of the original number)

Example: (13)10 à(----)2

Original #

division

Remainder

13

2

1

6

2

0

3

2

1

1

2

1

0

So the result will be (1101) 2

  • From binary to decimal: multiply each digit with 2 to the power of (0 to 7) in its order from right to left then sum the final result

Example: (1101)2à (….)10

Original #

1

1

0

1

Multiplication

1*23

1* 22

0*21

1* 20

Result for each digit

8

4

0

1

addition

13

So the result will be (13)10

Special case: fraction:

Example: (1101.10)2à (….)10

Original #

1

1

0

1

.

1

0

multiplication

1*23

1* 22

0*21

1* 20

.

1*2-1

0*2-2

Result for each digit

8

4

0

1

.5

0

addition

13

.

.50

So the result will be (13.5)10

  • From binary to octal: each 3 binary digits represents 1 octal digit

Octal= 23 binary

Example: (1011101) 2à (…) 8

Original #

1011101

Divide to 3 digits

001

011

101

Convert to decimal

1

3

5

Concatenate (result)

135


The result will be (135) 8

  • From octal to binary: convert each octal digit to its binary representation then concatenate the result

Example: (357) 8 à (…….)2

Original #

357

For each octal digit

3

5

7

Convert to binary

011

101

111

Concatenate (result)

011101111





The result will be (011101111)2

  • From binary to Hexadecimal: each 4 binary digits represents 1 hexadecimal digit

Hexadecimal= 24 binary

Example: (1011101) 2à (…) 16

Original #

1011101

Divide to groups of 4 digits

0101

1101

Convert to decimal

5

13

Convert to hexadecimal

5

D

Concatenate (result)

5D


The result will be (5D) 16

  • From Hexadecimal to binary: convert each hexadecimal digit to its binary representation then concatenate the result

Example: (D7B) 16 à (…….)2

Original #

D7B

Convert each hexadecimal digit to binary

1101

0111

1011

Concatenate (result)

110101111011

The result will be (110101111011)2

  • From any numbering system to decimal: multiply each digit by the target system base to the power of (0 to 7) in its order from right to left then sum the final result

Example: (247)8à (….)10

Original #

2

4

7

The digit multiplied by the Base to the power from 0-7 from R to L

2* 82

4*81

7* 80

Result for each digit

128

32

7

addition

167

So the result will be (167)10

  • From decimal to any numbering system: (divide the decimal number by the base of the target system then take the remainder –up right-to be the new representation of the original number)

Example: (4037)10 à(----)16

Original #

division

Remainder

4037

16

5

252

16

12àC

15

16

15àF

0

So the result will be (FC5) 16