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 — 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, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
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.
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, and the Java Academy course includes 3 lessons in total. 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.
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; this is — lesson 2 of 3, so you can start here or from the beginning and move at your own pace.
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