Now that we know what are **variables** and how do we assign them, its time to move on to something more advanced. Consider the statement below:

savings = 2000

savings = savings + 1000

Now if you come from a mathematical background, this probably wouldn’t make sense to you. How can savings on the left (2000) be equals to savings (2000) plus 1000, which is 3000. 2000 = 3000? That is just plain *nonsense*.

Well the equals sign in Python, as well as many other programming languages, isnt the same as equals. Rather it is an **assignment operator**. In other words when we write code such as `savings = 2000`

we are actually assigning the number `2000`

to the variable named `savings`

.

So python evaluates expressions in this manner, it looks at what is on the right of the assignment operator

savings = **savings + 1000**

As we have learned in Backus Naur form, the non-terminal terms will be replaced by terminal terms, and in this case savings is replaced by 2000, which we assigned in the prior statement:

savings = **2000 + 1000**

Python evaluates the addition:

savings = **3000**

And now this is simplified to an assignment expression, the value of savings is thus, 3000.

This is a very important concept that you will have to grasp and if you are still confused, feel free to ask questions in the comments section below.

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