# Number Systems, Add/Subtract, etc

#### TheTechGod

Joined Jun 15, 2005
8
Hi everyone,

I'm studying for an exam next week and need to catch up on some work that I missed. Most of this was discussed in class and is not in our textbook

I need help with tracking down some Number Systems tutorials. I already know how to convert whole numbers to/from Decimal, Binary, Hexadecimal, but I need some tutorials that explain how to convert from any base to any other base.

I'm also looking for some tutorials explaining how to do binary addition/subtraction using 2's compliment or 1's compliment. I need to know how this is done without converting to decimal first (which is how I currently do it).

I already know how to convert positive binary numbers to negative using 2's compliment.

Here are some questions from a practise exam that I'll need to know how to do:

Convert the following base 12 number into a base 15 number:
AB2.47

Perform the following binary long division to 4 binary point places:
1001101.1011 / 11.01

Perform the following binary multiplication:
101101.101 x 1011.11

Use 1's complement arithmetic (8 bit) to perform the following subtraction:
11.25 (base 10) - 14.625 (base 10)

Use 2's complement arithmetic (8 bit) to perform the following subtraction:
- 76 (base 10) - 51 (base 10)

In total, the number systems questions will be worth about 1/4'th of the exam, so I really do want to brush up on it. I don't need to go much more in depth than what the above questions ask for. Web tutorials would be best (I have tried searching but I keep running into floating point representation - which is beyond the scope of this subject)... If you know any good non-obscure books then please recommend them and I'll see if I can find them at the library.

Please help with anything you can, even if you can't cover everything.

Thanks everyone and sorry for the long post!

#### davidand

Joined Jun 2, 2005
43
Originally posted by TheTechGod@Jun 15 2005, 09:08 AM
Hi everyone,

I'm studying for an exam next week and need to catch up on some work that I missed. Most of this was discussed in class and is not in our textbook

I need help with tracking down some Number Systems tutorials. I already know how to convert whole numbers to/from Decimal, Binary, Hexadecimal, but I need some tutorials that explain how to convert from any base to any other base.

I'm also looking for some tutorials explaining how to do binary addition/subtraction using 2's compliment or 1's compliment. I need to know how this is done without converting to decimal first (which is how I currently do it).

I already know how to convert positive binary numbers to negative using 2's compliment.

Here are some questions from a practise exam that I'll need to know how to do:

Convert the following base 12 number into a base 15 number:
AB2.47

Perform the following binary long division to 4 binary point places:
1001101.1011 / 11.01

Perform the following binary multiplication:
101101.101 x 1011.11

Use 1's complement arithmetic (8 bit) to perform the following subtraction:
11.25 (base 10) - 14.625 (base 10)
Use 2's complement arithmetic (8 bit) to perform the following subtraction:
- 76 (base 10) - 51 (base 10)
In total, the number systems questions will be worth about 1/4'th of the exam, so I really do want to brush up on it. I don't need to go much more in depth than what the above questions ask for. Web tutorials would be best (I have tried searching but I keep running into floating point representation - which is beyond the scope of this subject)... If you know any good non-obscure books then please recommend them and I'll see if I can find them at the library.

Please help with anything you can, even if you can't cover everything.

Thanks everyone and sorry for the long post!
[post=8520]Quoted post[/post]​
http://www.duke.edu/~twf/cps104/twoscomp.html

#### TheTechGod

Joined Jun 15, 2005
8
Thanks, that is very helpful!

If anyone knows of anything else, please post it too. I'm still confused with multiplication/division...