1. Number Systems
Common Number Systems SystemBaseSymbols Used by humans? Used in computers? Decimal100, 1, … 9YesNo Binary20, 1NoYes Octal80, 1, … 7No Hexa- decimal 160, 1, … 9, A, B, … F No
Quantities/Counting (1 of 3) DecimalBinaryOctal Hexa- decimal
Quantities/Counting (2 of 3) DecimalBinaryOctal Hexa- decimal A B C D E F
Quantities/Counting (3 of 3) DecimalBinaryOctal Hexa- decimal Etc.
Conversion Among Bases The possibilities: Hexadecimal DecimalOctal Binary
Quick Example = = 31 8 = Base
Decimal to Decimal (just for fun) Hexadecimal DecimalOctal Binary Next slide…
=>5 x 10 0 = 5 2 x 10 1 = 20 1 x 10 2 = Base Weight
Binary to Decimal Hexadecimal DecimalOctal Binary
Binary to Decimal Technique –Multiply each bit by 2 n, where n is the “weight” of the bit –The weight is the position of the bit, starting from 0 on the right –Add the results
Example => 1 x 2 0 = 1 1 x 2 1 = 2 0 x 2 2 = 0 1 x 2 3 = 8 0 x 2 4 = 0 1 x 2 5 = Bit “0”
Octal to Decimal Hexadecimal DecimalOctal Binary
Octal to Decimal Technique –Multiply each bit by 8 n, where n is the “weight” of the bit –The weight is the position of the bit, starting from 0 on the right –Add the results
Example => 4 x 8 0 = 4 2 x 8 1 = 16 7 x 8 2 =
Hexadecimal to Decimal Hexadecimal DecimalOctal Binary
Hexadecimal to Decimal Technique –Multiply each bit by 16 n, where n is the “weight” of the bit –The weight is the position of the bit, starting from 0 on the right –Add the results
Example ABC 16 =>C x 16 0 = 12 x 1 = 12 B x 16 1 = 11 x 16 = 176 A x 16 2 = 10 x 256 =
Decimal to Binary Hexadecimal DecimalOctal Binary
Decimal to Binary Technique –Divide by two, keep track of the remainder –First remainder is bit 0 (LSB, least-significant bit) –Second remainder is bit 1 –Etc.
Example = ? =
Octal to Binary Hexadecimal DecimalOctal Binary
Octal to Binary Technique –Convert each octal digit to a 3-bit equivalent binary representation
Example = ? =
Hexadecimal to Binary Hexadecimal DecimalOctal Binary
Hexadecimal to Binary Technique –Convert each hexadecimal digit to a 4-bit equivalent binary representation
Example 10AF 16 = ? A F AF 16 =
Decimal to Octal Hexadecimal DecimalOctal Binary
Decimal to Octal Technique –Divide by 8 –Keep track of the remainder
Example = ? =
Decimal to Hexadecimal Hexadecimal DecimalOctal Binary
Decimal to Hexadecimal Technique –Divide by 16 –Keep track of the remainder
Example = ? = 4D = D
Binary to Octal Hexadecimal DecimalOctal Binary
Binary to Octal Technique –Group bits in threes, starting on right –Convert to octal digits
Example = ? =
Binary to Hexadecimal Hexadecimal DecimalOctal Binary
Binary to Hexadecimal Technique –Group bits in fours, starting on right –Convert to hexadecimal digits
Example = ? B B = 2BB 16
Octal to Hexadecimal Hexadecimal DecimalOctal Binary
Octal to Hexadecimal Technique –Use binary as an intermediary
Example = ? E = 23E 16
Hexadecimal to Octal Hexadecimal DecimalOctal Binary
Hexadecimal to Octal Technique –Use binary as an intermediary
Example 1F0C 16 = ? 8 1 F 0 C F0C 16 =
Exercise – Convert... Don’t use a calculator! DecimalBinaryOctal Hexa- decimal AF Skip answer Answer
Exercise – Convert … DecimalBinaryOctal Hexa- decimal C AF Answer
Common Powers (1 of 2) Base 10 PowerPrefaceSymbol picop nanon micro millim 10 3 kilok 10 6 megaM 10 9 gigaG teraT Value
Common Powers (2 of 2) Base 2 PowerPrefaceSymbol 2 10 kilok 2 20 megaM 2 30 GigaG Value What is the value of “k”, “M”, and “G”? In computing, particularly w.r.t. memory, the base-2 interpretation generally applies
Example / 2 30 = In the lab… 1. Double click on My Computer 2. Right click on C: 3. Click on Properties
Exercise – Free Space Determine the “free space” on all drives on a machine in the lab Drive Free space BytesGB A: C: D: E: etc.
Review – multiplying powers For common bases, add powers 2 6 2 10 = 2 16 = 65,536 or… 2 6 2 10 = 64 2 10 = 64k a b a c = a b+c
Binary Addition (1 of 2) Two 1-bit values ABA + B “two”
Binary Addition (2 of 2) Two n-bit values –Add individual bits –Propagate carries –E.g.,
Multiplication (1 of 3) Decimal (just for fun) 35 x
Multiplication (2 of 3) Binary, two 1-bit values AB A B
Multiplication (3 of 3) Binary, two n-bit values –As with decimal values –E.g., 1110 x
Fractions Decimal to decimal (just for fun) 3.14 =>4 x = x = x 10 0 =
Fractions Binary to decimal => 1 x 2 -4 = x 2 -3 = x 2 -2 = x 2 -1 = x 2 0 = x 2 1 =
Fractions Decimal to binary x x x x x x etc
Homework – Convert... Please provide with your full answers steps DecimalBinaryOctal Hexa- decimal C.82
Homework Answer– Convert … DecimalBinaryOctal Hexa- decimal …35.63…1D.CC… D C C.82 Answer