Binary Lesson 1

• Computing
• Lower Secondary (Key Stage 3)

Binary Basics: Understanding Numbers in Computing

Do now: Can you count to 31 using one hand? You can only use each finger once.
How could you do this?

Counting to 31 with one hand 

We can count to 31 using one hand by giving different values to each of our fingers. When we add all of these values together we get 31. 

Learning Objectives

Strengthening: Understand the purpose of denary and binary, 

Excelling: interpret the binary number line and convert between denary and binary.

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 Binary?

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

• What could those digits be? 

• Hint: Computers run on electricity. electricity can only be on or off

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. 

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 to 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. 

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. 

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.

Make the number 13 in binary.

Make the number 7 in binary.

Make the number 10 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

What is the number 12 in binary?

1. 1100
2. 0001
3. 1111
4. 0011

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. 

Make the number 20 in binary.

Make the number 46 in binary.

Make the number 103 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. 

Binary bulbs 

Binary Game

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.