1. Revision Introductory Lesson
Number Systems
Decimal | Binary | Hexadecimal
Revision Introductory Lesson

2. In this topic … Decimal System Binary System Hexadecimal System
Conversions

3. Conversions … Binary  Decimal Decimal  Binary Binary  Hexadecimal
Decimal  Hexadecimal
Hexadecimal  Binary

4. Decimal System Ten fingers Ten different numbers possible:
Base 10 e.g

5. 6 5 4 2 Our Number System 6 5 4 2 100 = 1x 2 = 2 101 = 10 x 4 = 40
6542
tens
units
hundreds
thousands … …

6. Binary System Switch Two possible values: 0 and 1
Base 2 E.g

7. Binary System … …
MSB
LSB
Most Significant Bit
Least Significant Bit
The bit position having the greatest value
The bit position having the least value

8. Binary to Decimal Conversion
Q: Convert to decimal. A:
128 64 32 16 8 4 2 1 1 1 1 1 1
Add together the corresponding values where there is a 1
= 11710

9. Decimal to Binary Conversion Method 1 – Using Long Division
Q: Convert 1810 to binary: A: 2 18 2 9
r 0
1810 = 2 4
r 1 2 2
r 0 2 1
r 0
r 1

10. Decimal to Binary Conversion
Method 2 – Using Weights
Q: Convert to binary. A:
128 64 32 16 8 4 2 1 1 1 1 1 1 2
Working:
173 –
128
45 – 32
13 – 8
5 – 4
1 – 1 45 13 5 1

11. Any Questions?