This program has 4 instructions, or statements, each on a different line.

It uses 3 variables, called a b and c. The values of these variables change as the instructions are carried out. The current values of the variables is shown in the column headed 'Now', shown on the right.

Click on the Step button and see what happens. Click on Reset to start again.

When you have the idea, type in what you think the next values of the variables will be before you click Step. The cell goes green if you were right, and your score goes up.

The pattern of this program is
Initialise variables
Calculate result
Output the result

Once you understand this, write these programs:

Initialise a as 2 and b as 3
Make c equal to a times b (use * for multiply)
Output c

Finding the average of two numbers, by adding them up and dividing by 2:
Initialise a as 2 and b as 4
Make c equal to (a+b)/2 .. we need the brackets so it adds first
Output c
Try other values of a and b to check it works

Finding the volume of a cuboid:
Initialise a as 2, b as 3, c as 4
Make d equal to a times b times c
Output d