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Simple Java Maths

Explore Java's basic math operations, including addition, subtraction, multiplication, division, and modulus. Understand the order of operations (BODMAS) and operator associativity to correctly evaluate expressions and write reliable Java code.

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Introduction

Math in Java is very simple. Keep in mind that Java mathematical operations follow a particular order much the same as high school math.

For example, multiplication and division take precedence over addition and subtraction. The order in which these operations are evaluated can be changed using parentheses.

Operations in Java

The arithmetic operators in Java are listed below.

Symbols Arithmetic operators
+ add
- subtract
/ divide
* multiply
% modulus division
++ post and pre-increment
-- post and pre-decrement

Example

Let’s take a look at how to use these operations while coding in Java.

Java
public class Operators {
    public static void main(String[] args) {
        int answer; 
        System.out.println("ADDITION");
        int add = 20;
        System.out.println("Initial value: " + add);
        answer = add + 2;
        System.out.println("add + 2 = " + answer);
        answer = add;
        System.out.println("add = " + answer);
        System.out.println();
        System.out.println("SUBTRACTION");
        int sub = 15;
        System.out.println("Initial value: " + sub);
        System.out.println("sub - 4 = " + (sub - 4));
        System.out.println("sub = " + sub);
        System.out.println();
        System.out.println("MULTIPLICATION");
        int mult = 25;
        System.out.println("Initial value: " + mult);
        answer = mult * 3;
        System.out.println("mult * 3 = " + answer);
        answer = mult;
        System.out.println("mult = " + mult);
        System.out.println();
        System.out.println("DIVISION (INT)");
        int div_int = 15;
        System.out.println("Initial value: " + div_int);
        System.out.println("div_int / 2 = " + (div_int / 2));
        System.out.println("div_int = " + div_int);
        System.out.println();
        System.out.println("MODULO (REMINDER)");
        int rem = 5;
        System.out.println("Initial value: " + rem);
        answer = rem % 2;
        System.out.println("rem % 2 = " + answer);
        answer = rem;
        System.out.println("rem = " + answer);
        System.out.println();
        System.out.println("PREINCREMENT BY ONE");
        int pre_inc = 5;
        System.out.println("Initial value: " + pre_inc);
        System.out.println("++pre_inc   = " + (++pre_inc));
        System.out.println("pre_inc = " + pre_inc);
        System.out.println();
        System.out.println("PREDECREMENT BY ONE");
        int pre_dec = 5;
        System.out.println("Initial value: " + pre_dec);
        answer = --pre_dec;
        System.out.println("--pre_dec   = " + answer);
        answer = pre_dec;
        System.out.println("pre_dec = " + answer);
        System.out.println();
        System.out.println("POST INCREMENT BY ONE");
        int post_inc = 5;
        System.out.println("Initial value: " + post_inc);
        System.out.println("post_inc++   = " + (post_inc++));
        System.out.println("post_inc = " + post_inc);
        System.out.println();
        System.out.println("POSTDECREMENT BY ONE");
        int post_dec = 5;
        System.out.println("Initial value: " + post_dec);
        answer = post_dec--;
        System.out.println("post_dec--   = " + answer);
        answer = post_dec;
        System.out.println("post_dec = " + answer);
        System.out.println();
    }
}

Operator precedence

Operator precedence specifies the order in which operations will execute provided that the expression contains more than one operator. With mathematical operations, the precedence follows the rule of BODMAS, which says; Brackets, Order, Division, Multiplication, Addition, and then Subtraction. Let’s look at an example below to check this!

For the purpose of these examples, we will set the following variables; ...