year 7 binary Lesson

• Computing
• Lower Secondary (Key Stage 3)

Binary Basics: Understanding Numbers in Computing

Learning Objectives

By the end of this lesson you will know, what binary is and how it compares to our denary system.

What is Denary?

Denary, or decimal, is called a base-10 number system. 

• It uses the digits 0-9. It's the most common system for everyday counting and arithmetic

• We use 0-9 to make every other number that exists.
• 127
• 1024

What is denary?

The denary or decimal system is the way we usually count and do maths.

It’s called a base-10 system because it uses 10 digits — 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

We can make any number in the world using just these 10 digits!

For example:

• We use 1, 2, and 7 to make 127
• We use 1, 0, 2, and 4 to make 1024

So, every big number you see is just made by putting these digits together in different ways!

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

What is Binary?

What is binary ?

Binary is the language computers use, it is a base-2 number system. Meaning It uses only two digits:

What could those digits be?

Hint: Computers run on electricity. What state can electricity be in?

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

What is Binary?

Binary is a base-2 number system. It uses only two digits:

• We use 1 and 0 in binary.
  
• 1 means on and 0 means off.
  
• These are the only 2 numbers we are allowed to use. 

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

Which of these is an example of a denary number?

1. 1010101
2. 101010101
3. 01010101
4. 127

Which of these is an example of a Binary number?

1. 10101031010
2. 1010120102
3. 01010101
4. 127

What digits do denary numbers use

1. 1 and 2
2. 0 to 9
3. 10 to 20
4. 1 to 10

Which 2 numbers do we use in binary?

1. 1 and 2
2. 9 and 10
3. 0 and 1
4. 5 and 6

Binary Number Line

The binary number line is very different to how we normally count. 

• Here is the full binary number line. 

• You can see we double each time we move forward. 

Denary number line (base 10)

Thousands

Hundreds

Tens

Units/Ones

x10

x10

x10

4,217

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

Binary number line (base 2)

• You can see we double each time we move forward. 

8

4

2

1

x2

x2

x2

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

How do we change denary numbers to binary?

Computers do not understand the numbers we use, they have to be changed so the computer can understand them. 

Computers do not understand the numbers we use, they have to be changed so the computer can understand them. 

• Remember the 0's and 1's

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

Pre-watch the video to help. the students will then have a go at some simple conversions. 

Make the number 3 in binary.

Make the number 9 in binary.

What is the number 2 in binary?

1. 0001
2. 0010
3. 1111
4. 0000

What is the number 15 in binary?

1. 0001
2. 0010
3. 1111
4. 0000

Why do we convert into binary?

1. To shorten the number
2. Its the only way the computer can understand numbers.
3. To test our skills.
4. To save time.

Larger number 

Computers have to deal with very large numbers all of the time. so we extend the number line by doubling the numbers. 

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

Make the number 20 in binary.

Make the number 46 in binary.

Make the number 255 in binary.

Converting back

The computer will also convert the numbers back again on our screens so we can understand them:

• 0101
• 
  

• 4 + 1 = 5

8	4	2	1
0	1	0	1

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

Click here to practice binary

Binary Game

LO - By the end of this lesson you will know, what binary is and how it compares to our denary system.

If need a game on the board for conversion, to could use this to test knowledge, award points, ask kids to come up to the board, or play by themselves. 

What is binary?

What did you learn today?