1. Advanced Binary b. describe and use two’s complement and sign and magnitude to represent negative integers; c. perform integer binary arithmetic, that is addition and subtraction; d. explain the use of code to represent a character set (ASCII, EBCDIC and UNICODE);

2. Negative binary As well as positive numbers Binary can also be used to represent Negative numbers. (-19,-18 etc). There are a number of ways of displaying negative numbers. You must know 2: 1.Sign and Magnitude 2.Twos Complement

3. Sign & Magnitude The MSB is used as a sign bit. 1 for - 0 for + So 1011 would mean -3 NOT 11

4. Twos complement 11111101 = -3 11111110 = -2 11111111 = -1 00000000 = 0 00000001 = 1 00000010 = 2 00000011 = 3 How can you tell if its -3 or 253? The exam question will tell you!

5. Convert negative denary to binary. Convert negative denary to binary: 1.Find the positive binary value 2. Starting from the right leave all the digits alone ppup to and including the first 1. 3. Change all the other digits from 0 to 1 or 1 to 0.

6. Convert – 12 to binary: 1. Find the positive binary value 00001100 2. Starting from the right leave all the digits alone up to and including the first 1. 00001100 3. Change all the other digits from 0 to 1 or 1 to 0. 11110100

7. Binary addition 1001101 + 0010010 0+0 = 0 1+0 = 1 0+1=1 1+1=10 1+1+1=11

8. Binary addition 1001001 + 0011001 0+0 = 0 1+0 = 1 0+1=1 1+1=10 1+1+1=11 1100010 11 1 Carry bits

9. Binary subtraction Convert the number to be subtracted into a negative number THEN add them together. 7 - 5 = ? 7 = 0111 -5 = 1011

10. Binary subtraction 7 = 0111 -5 = 1011 0111 + 1011 0010 The extra bit is discarded

11. Representing a Characters set using Binary ASCII UNICODE EBCDIC Find out what each of the above are and why they are used. Write it into your notes.

12. ABCD < abcd