1. Binary
It’s all 0’s and 1’s

2. Objective for the rest of the Lesson
You will be able to convert denary to binary and back again!
How to add to add 2 different binary numbers together

3. Units The most basic and smallest piece of computer data is a bit
8 bits = 1 byte
We then measure everything in bits not bytes
So kilobyte – 1024 bytes

4. So what is Binary? Humans use the denary number system
Computers use 1 and 0 hence BINARY
Its all about what the CPU is reading
0 a switch is open 1 its closed

5. On Paper! It all about tables! Binary only goes from 0-255
128 64 32 16 8 4 2 1
Denary 86
149
255
It all about tables!
Binary only goes from 0-255
Use this chart and you can’t go wrong!

6. Adding Binary
0 + 0 = 0
1 + 0 = 0
1 + 1 = 10
= 11
Confused?

7. Let me explain The first 2 rows are the 2 numbers you are adding1
The first 2 rows are the 2 numbers you are adding
The third row is where the carrying goes
The bottom row is the answer

8. Stage 1 From the rules earlier we know that 1+1=101
From the rules earlier we know that 1+1=10
So 0 goes in the fourth row and the 1 carries over

9. Row 2 is now 0+1+1 which is 10 so the same happen again
Stage 2 1
Row 2 is now which is 10 so the same happen again

10. Row 3 is now 1+0+1 which is 10 so the same happen again
Stage 3 1
Row 3 is now which is 10 so the same happen again

11. Row 4 is now 1+1+1 which is 11 so the same happen again
Stage 4 1
Row 4 is now which is 11 so the same happen again

12. Carry this on until… 1
Simple?

13. Overflow?
The biggest number you can represent with 8 bits is 255 ( )
(252)
(15)
(267)
The computer would need 9 bits to represent 267 so this 9th bit doesn’t fit in the byte allocated. This is overflow.

14. Finally I need a volunteer…. Tell the class about units
What about denary and binary
Hands up if you love 1’s and 0’s