8_1_5

Activity 2 - READ

There are four golden rules for Binary Addition:

Rule 1 0 + 0 = 0 (0 + 0 = 0 in decimal)

Rule 2 0 + 1 = 1 (0 + 1 = 1 in decimal)

Rule 3 1 + 1 = 10 (1 + 1 = 2 in decimal)

Rule 4 1 +1 + 1 = 11 (1 + 1 + 1 = 3 in decimal)

Study the following animations to learn what happens when two small numbers are added together:

1 + 1 (1+1 = 2 in decimal)

1 + 10 (1 + 2 = 3 in decimal)

Activity 3

Try it yourself:

• 1 + 11 = ?

• 10 + 10 = ?

• 11 + 10 = ?

• 11 + 11 = ?

Remember the golden rules!

You can check your working by converting the numbers to decimal numbers and checking your maths.

Activity 4

If you were correct then try the examples on the worksheet below:

Binary Maths Questions (Google Sheet)

(self mark using http://www.calculator.net/binary-calculator.html )

Activity 1 - READ

Subtraction also has some golden rules. Think back to when you first learnt how to subtract numbers in primary school. It is a little bit like that!

There are four golden rules for Binary Subtraction:

Rule 1 0 - 0 = 0 (0 - 0 = 0 in decimal)

Rule 2 1 - 1 = 0 (1 - 1 = 0 in decimal)

Rule 3 1 - 0 = 1 (1 - 0 = 1 in decimal)

Rule 4 0 - 1 = 1 (*requires borrowing)

1 - 1 = 0 (1 - 1 = 0 in decimal)

0100 - 0010 = 0010 (4 - 2 = 2 in decimal)

Activity 2

Try some yourself:

• 11 - 11 = ?

• 10 - 01 = ?

• 111 - 1 = ?

(self mark using http://www.calculator.net/binary-calculator.html )

Activity 3

If you are starting to understand it now, try the worksheet below:

Binary Maths Question Subtract

Create a binary maths test for another student in your class to try. You should create the question sheet and the answers. You can then swap question sheets and try each others out.

Re-enforce the golden rules for addition and subtraction. This will help the students complete the arithmetic quickly. This is best completed as a teacher led activity with lots of practice at trying different difficulty levels.