1. Binary Systems
GCSE Computer Science

2. Binary Numbers Recognise the use of binary numbers in computer systems
Click here for Topic Introduction

3. A base is the number of digits in a number system.
Binary = 2
Denary = 10
Octal =
Duodecimal =
Hexadecimal =
Number Bases
A base is the number of digits in a number system.

4. Binary As A Language
Using electricity, what would the bit pattern mean?
Computers use binary to store and transmit data, but they need a way to understand what we see as 1 & 0...

5. Binary Conversion
Convert positive denary integers into binary and positive binary integers into denary (a maximum of 16 bits will be used)

6. 128 64 32 16 8 4 2 1 =
Binary To Denary
Converting to denary requires all columns to be added where there is a 1.
128 64 32 16 8 4 2 1 =
128 64 32 16 8 4 2 1
= = 42
128 64 32 16 8 4 2 1 =

7. Write out the steps shown below to convert from denary to binary
128 64 32 16 8 4 2 1 25
Denary to Binary
Write out the steps shown below to convert from denary to binary
128 64 32 16 8 4 2 1
205
128 64 32 16 8 4 2 1 42
= 10
= 2
2 - 2 = 0
128 64 32 16 8 4 2 1
255

8. 256
128 64 32 16 8 4 2 1 =
Larger Numbers
For larger numbers, the most significant bit is doubled for each additional column
256
128 64 32 16 8 4 2 1 =
MSB
LSB
256
128 64 32 16 8 4 2 1
= = 298
256
128 64 32 16 8 4 2 1 =

9. Memory Sizes
Show understanding of the concept of a byte and how the byte is used to measure memory size
Click here for topic introduction

10. Memory Sizes
Byte
Put the memory in order of size showing how memory size is calculated.
Annotate to show how much memory is in the next size.
Bit
Gigabyte
Terabyte
Megabyte
Kilobyte
Nibble

11. Calculating Memory Sizes
2.5 Kilobytes
5 Gigabytes
Show how you would calculate how many files of a certain type would fit into a storage device of a larger size.

12. Exam Questions Recognise the use of binary numbers in computer systems
Convert positive denary integers into binary and positive binary integers into denary (a maximum of 16 bits will be used)
Show understanding of the concept of a byte and how the byte is used to measure memory size
Use binary in computer registers for a given application (such as in robotics, digital instruments and counting systems)

13. Exam Question 1

14. Exam Question 1a

15. Exam Question 1b

16. Exam Question 2

17. Answers
8 bits / An 8 bit unit of memory 30