converting decimal to binary, binary to octal, octal to decimal, hex to decimal, binary to hex, and binary to octal

A. Decimal to binary
Decimal has 10 digit numbers include 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and Binary has 2 digit numbers include 0 and 1.
How to convert Decimal to binary?
For example:
211(10) = .........(2)?
Answer:
211/2 = 105 rest 1
105/2 = 52 rest 1
52/2   = 26 rest 0
26/2   = 13 rest 0
13/2   = 6 rest 1
6/2     = 3 rest 0
3/2     = 1 rest 1
then arrange the rest from the bottom to up and be like this 1010011(2).

B. Binary to decimal
For example:
 
C. Binary to octal
Octal has 8 digit numbers include 0,1,2,3,4,5,6,7.
How to convert binary to octal 100001101111(2) = ..........(8)?  
First, give bulkhead on each 3-digit numbers as below:
 
100(2) = 4(8) 
001(2) = 1(8) 
101(2) = 5(8) 
111(2) = 7(8)   
So, the octal numbers're 4157.

D. Octal to decimal
1124(8) = ..............(10)?
Answer:
=(1*8^3)+  (1*8^2)+  (2*8^1)+  (4*8^0)
=(1*512)+(1*64)+(2*8)+(4*1)
= 512+64+16+4
=596

D.  Hex to decimal
Hex has more than 9 digit numbers.Include  0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. A same with 10, B same with 11, C same with 12, D same with 13, E same with 14, and F same with 15.
How to convert DCB12(16) = ...............(10)?
Answer:
=(13*16^4)+(12*16^3)+(11*16^2)+(1*16^1)+(2*16^0)
= (13*65536)+(12*4096)+(11*256)+(1*16)+(2*1)
=851968+49152+2816+16+2
=903954

E. Biner to hex
How to convert 1101111000110101(2)=....................(16) 
First, give bulkhead on each 4-digit numbers as below:
 


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