# Operators

### 1. Let’s do Math: Arithmetic Operator

In the last exercise, we learn about variables any how we can assign values to a variable of a specific type, such as:

``````int age = 3;  // declare variable age of type int with value 3
age = 4;      // assign 4 to the variable age
``````

Looking at the code above, it essentially add 1 to the value of the variable `age`.

And, in Java, we can perform math operations on variables directly with arithmetic operators: `+`, `-`, `*`, `/`, `%`. For example, we can use the add operator `+` to add 1 to `age`:

``````int age = 3;  // declare variable age of type int with value 3
age = age + 1;// add 1 to age
``````

### 2. Comparisons: Relational Operator

Next, let’s learn how to compare numbers. Let me introduce the relational operators.

Just like in math, we can compare numbers using `>`, `<`, `>=`, `<=`. For example: `(3 > 2)` is `true`, a boolean value.

### 3. Exam Statistics!

Patrick 🐥 and 4 of his classmates just had a music exam in this class. These are the grades of their exams: Patrick(88), Tom(89), Mary(95), Chris(84), Jen(92).

We want to produce a grade statistic report of the whole class.

This report list of students grade, class average score, and whether class average is over 60, 70, 80, 90 (`true` or `false`), like the following:

``````---------------------------
---------------------------