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Subtract Two Numbers in Java

beginner· Basics & I/O · Arithmetic

Problem

Subtracting two numbers with the - operator finds the difference between them.

Given two integers, subtract the second from the first and print the result.

Input

10, 4

Output

Difference: 6

Java Program

Java

public class SubtractTwoNumbers {
    public static void main(String[] args) {
        int a = 10;
        int b = 4;
        int difference = a - b; // order matters here
        System.out.println("Difference: " + difference);
    }
}

▶ Run Code

Output

Difference: 6

Core Logic

The - operator subtracts the second value from the first, evaluated left to right just like standard arithmetic.

How It Works

1a holds 10 and b holds 4.
2a - b evaluates to 6, the result of subtracting b from a.
3The result is stored in difference and printed alongside a label.

With a = 10 and b = 4, a - b evaluates to 6, so the program prints "Difference: 6".

💡

Key Point: Order matters with subtraction — a - b and b - a give different (often negatively signed) results, unlike addition or multiplication.

Key Concepts

- operatorintarithmetic

Approach 2: Java 8

Java

import java.util.function.IntBinaryOperator;

public class SubtractTwoNumbersLambda {
    public static void main(String[] args) {
        int a = 10;
        int b = 4;
        // Order still matters inside the lambda — this computes a - b, not b - a
        IntBinaryOperator subtract = (x, y) -> x - y;
        int difference = subtract.applyAsInt(a, b);
        System.out.println("Difference: " + difference);
    }
}

▶ Run Code

Output

Difference: 6

Core Logic

Subtraction can be captured the same way as addition — a lambda stored in an IntBinaryOperator instead of an inline expression.

How It Works

1IntBinaryOperator subtract = (x, y) -> x - y; stores the subtraction logic as a value.
2subtract.applyAsInt(a, b) runs the lambda with a and b, in that order, since subtraction isn't commutative.
3The result is stored and printed exactly as before.

With a = 10 and b = 4, subtract.applyAsInt(10, 4) evaluates x - y and returns 6.

💡

Key Point: Order still matters inside the lambda body — subtract.applyAsInt(b, a) would silently give the wrong sign, same trap as writing b - a directly.