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Do Some Math

Do Some Math

Perform basic math operations in Java and print results.

We'll cover the following...

Now let’s turn Java into your personal calculator. You’ll use arithmetic operators to do math and instantly see the results.

Goal

You’ll aim to:

  • Perform basic math operations.

  • Use System.out.println() with numbers.

  • Store results in variables.

Add and subtract

Let’s start by adding and subtracting two numbers. Java will do the math and print the results:

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public class Main {
    public static void main(String[] args) {
        System.out.println(10 + 5);  // 15
        System.out.println(10 - 3);  // 7
    }
}

Java evaluates the math before printing it.

Nice work! You just made Java do the math for you.

Multiply and divide

Let’s try multiplying and dividing two numbers to see the results:

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public class Main {
    public static void main(String[] args) {
        System.out.println(6 * 4);  // 24
        System.out.println(20 / 5); // 4
    }
}

When you divide integers in Java, you only get the whole number part of the answer—no decimals.

Great job! You’ve successfully multiplied and divided the numbers and printed the results!

% Modulo (Remainder)

Let’s try the modulo of two numbers to see the results:

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public class Main {
    public static void main(String[] args) {
        System.out.println(10 % 3); // 1
    }
}

% gives you the remainder.

Great job! You’ve successfully printed the remainder.

Arithmetic Operator

Operation

Example

+

Addition

10 + 5 results in 15

-

Subtraction

10 - 5 results in 5

*

Multiplication

10 * 5 results in 50

/

Division

10 / 5 results in 2

Mini challenge

Create a program that:

  • Adds three numbers.

  • Multiplies two numbers.

  • Divides a number in half.

Example:

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public class Main {
    public static void main(String[] args) {
        // Write your code here
    }
}

If you’re stuck, click the “Show Solution” button.

You did it! Another challenge complete. Java math? Nailed it.

What’s next?

You’ve made Java do math. Next: store things properly using variables—and understand types like int, double, and boolean!