# Homework Help: Subtraction using 8-bit binary 1's complement

1. Apr 12, 2015

### Duderonimous

1. The problem statement, all variables and given/known data
Perform the indicated subtraction using 8-bit binary in 1's complement:

(22-59)10

(-11-64)10

2. Relevant equations
i. Convert the numbers from decimal to binary
ii. Take the ones complement of binary representation of any negative numbers
iii. Add the two numbers together add 1 if there is a carryout. Leave as is if no carry out.
3. The attempt at a solution
(+22)10 →→ (0001 0110)2 →→ (0001 0110)2
+(-59)10 → +1'sC(0011 1011)2 → +(1100 0100)2

(-11) →→1'sC(0000 1011)→1111 0100
+(-64) →+1'sC(0100 0000) →+1011 1111

Is this correct? Thanks. I just get the positive value by taking the 1's Comp of my answer right? I kind of figured it out as I wrote this. But if someone can confirm that would be nice thanks.

Last edited: Apr 12, 2015
2. Apr 12, 2015

### phinds

I only checked the first one and it looks fine.

3. Apr 12, 2015

Thanks