It's different because a variable in computer science is like a box that stores many answers while in math there is only one variable.
The two types would be setting the variable and changing a variable. It will affect what the variable is.
It can store as many values as it wants.
It will not work because value 1 is value 2 but value 2 is value 1 so it's like an infinite loop.
This is just like question 4 because all the values equal eachother so it will go on and on and on.