Input & Expressions – Part 1
Read numeric input with Scanner, apply arithmetic operators, and understand precedence and integer vs floating-point division.
Input & Expressions – Part 1 is a free Java Academy lesson on CoddyKit. This is lesson 2 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Java Academy learning path, and your progress syncs across the web and the CoddyKit app. The Java Academy course includes 3 lessons in total.
Lesson Goals
Goals
- Read numbers with
Scanner. - Use
+ - * / %. - Understand precedence and integer vs floating division.
Scanner Setup
Scanner setup
import java.util.Scanner;
Scanner sc = new Scanner(System.in);Use sc to read input from the keyboard in the console.
Read Numbers
Read numbers
int a = sc.nextInt();
double price = sc.nextDouble();Programs wait for input when using these calls.
Operators & Order
Operators: + - * / %
* / %happen before+ -.- Use parentheses to control order:
(a + b) * c. %is remainder.
Division Types
Division types
5 / 2→ integer division =2.5 / 2.0or(double)5 / 2→2.5.- Cast before dividing to get a precise result.
Input & Ops Demo
Try it: Enter two integers. Compare integer vs double division and check the remainder.
public class Main {
public static void main(String[] args) {
int a = 12;
int b = 5;
System.out.println("a = " + a + ", b = " + b);
System.out.println("a + b = " + (a + b));
System.out.println("a - b = " + (a - b));
System.out.println("a * b = " + (a * b));
System.out.println("a / b (int) = " + (a / b));
System.out.println("a / b (double) = " + ((double) a / b));
System.out.println("a % b = " + (a % b));
}
}
2.5 Expressions
Quick check: Which expressions evaluate to 2.5?
Recap & Next
Recap: You used Scanner for numeric input, applied operators with precedence, and practiced integer vs floating division.
Next: Work with strings and nextLine() safely, then parse numbers from text.
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Frequently Asked Questions
Is the “Input & Expressions – Part 1” lesson free?
Yes — the full text of “Input & Expressions – Part 1” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Java Academy course, upgrade to CoddyKit PRO. The Java Academy course includes 3 lessons in total.
What will I learn in “Input & Expressions – Part 1”?
Read numeric input with Scanner, apply arithmetic operators, and understand precedence and integer vs floating-point division. You practise Java Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Java Academy?
No prior experience is required. Java Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 3.
How long does the “Input & Expressions – Part 1” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Java Academy lesson?
Yes. Every Java Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Variables & Data Types
- Input & Expressions – Part 1
- Input & Expressions – Part 2