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!

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