1. Algorithms with variables that are assigned a number
By Phil Bagge
HIAS Computing Inspector/Advisor
CAS Master Teacher

2. Variable are like whiteboards
name
my_num 4
value

3. 4 Assigning a value name my_num value
When we write a value onto a variable we call it assigning a value 4
value

4. Read the name get the value
my_num
I am my_num years old.
Becomes
I am 4 years old
I have my_num friends.
becomes 4
value
I have 4 friends.

5. More read the name get the value
Assign 3 to variable called my_num Stand up Bow my_num times Sit down Wave my_num times Say my_num my_num Now write your own algorithm Don’t assign too large a number
Assign 4 to fav_num Say Hi fav_num times Hum for fav_num seconds Do fav_num times stand sit Jump fav_num times

6. We can change the value assigned to a variable
Now write your own algorithm with a changed value
Don’t assign too large a number
We can change the value assigned to a variable
Assign 5 to variable called my_num Stand up Bow my_num times Subtract 2 from my_num Say my num Sit down Wave my_num times Add 1 to my_num Say my_num
Assign 2 to fav_num Say Hi fav_num times Add 3 to fav_num Hum for fav_num seconds Subtract 2 from fav_num Do fav_num times stand sit Say fav_num
You can use a whiteboard to keep track of the value

7. Assigning a value to all variables at the beginning is called initialising the variables
Initialised variable
Assign 5 to variable called my_num Stand up Bow my_num times Subtract 2 from my_num Say my num Sit down Wave my_num times Add 1 to my_num Say my_num
On which line has the variable been initialised?