# Increment and decrement operations in JavaScript

Consider the following code:

`let num = 0; num = num + 1; // add the number 1 to the variable num alert(num); // shows 1`

As you already know, this code can be rewritten in an shortened form through the operator `+=`:

`let num = 0; num += 1; // add the number 1 to the variable num alert(num); // shows 1`

In fact, adding one in programming is so common that an even more shortend syntax has been invented for this operation - the special operator increment `++`, which increases the value of a variable by `1`.

Let's rewrite our code with it:

`let num = 0; num++; // add the number 1 to the variable num alert(num); // shows 1`

There is also the operation decrement `--`, which decreases the value of a variable by `1`. See an example:

`let num = 0; num--; // subtract the number 1 from the variable num alert(num); // shows -1`

Modify this code such a way that it contains increment and decrement operations:

`let num = 10; num = num + 1; num = num + 1; num = num - 1; alert(num);`
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