Anyone Know Anything About BCD (Binary Coded Decimal)

[efcrichie]

Help is needed with the following 5 questions:

Perform the following in BCD

Q1. 199 + 55 Decimal

Q2. 599 -10299 And

Q3. FFE + 6FD Hex

Q4. 77 - 53 Octal

Q5. 0100111 - 0110111 Binary

I don't have a clue and there are few web resources.
Help is urgently needed thanks to all

[OS Master]

I would probably start at Wikipedia (http://en.wikipedia.org/wiki/Binary-coded_decimal#Basics), since I unfortunately don't know anything about BCD.

[JoshC]

after looking at wiki a bit.....
Q1
199 + 55
0001 1001 1001
0000 0101 0101
============
0001 1110 1110

which in BCD any no greater than 9 isn't possible, so add 6 to each set greater than 9

0001 1110 1110
0000 0110 0110
============
0010 0101 0100

remembering to carry all the 1's

making 2 5 4

so 199 + 55 does equal 254
that for question 1 (didn't get a chance to read much of the rest of the wiki article)

[Tazfan]

yes i learnt about it a bit what do you want to know about it ?

[JoshC]

I can also do Q3, maybe I should have read up on subtracting too...

FFE + 6FD
0000 1111 1111 1110
0000 0110 1111 1101

0001 0110 1111 1011

which equals 1 6 F B

[QueenZ]

I'm also not an expert in Binary Decimals but wikipedia has a very great article about it and you can also take a look at this page if it help.. http://www.tpub.com/neets/book13/53s.htm