Learn

In our bank account example from the last exercise, we used the `+` operator to add the values `balance` and `depositAmount`:

``````double balance = 20000.99;
double depositAmount = 1000.0;
balance = balance + depositAmount;
// balance now holds 21000.99``````

If we wanted to withdraw from the balance, we would use the `-` operator:

``````double withdrawAmount = 500;
balance = balance - withdrawAmount;
// balance now holds 19500.99``````

Addition and subtraction work with `int` type values as well! If we had `60` pictures of cats on our phone, and we took `24` more, we could use the following line of code to store `84` in `numPicturesOfCats`.

``int numPicturesOfCats = 60 + 24;``

What if we took one additional picture of our cat? We can reflect this change using an increment operator `++`. When we append `++` to a number-based variable, it increases the value by `1`. We also have the decrement operator, `--`, which decreases the value by `1`.

``````// Take a picture
numPicturesOfCats++ // Value is now 85

// Delete a picture
numPicturesOfCats-- // Value is now 84``````

### Instructions

1.

Create an `int` variable called `animalsInZoo` that holds the amount of zebras plus the amount of giraffes at the zoo.

Then, print your `animalsInZoo` variable.

2.

Two of the zebras have been traded to a neighboring rival zoo. Subtract 2 from the number of zebras and store the result in a variable called `numZebrasAfterTrade`.

Then, print the `numZebrasAfterTrade` variable!