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Math class

Learn math operations with Math.abs and Math.max.

What is the Math class?

The Math class holds the mathematical methods from the Java standard library. All methods are static, so you call them as Math.methodName without creating an object.

Common methods:

  • Math.abs(x): absolute value
  • Math.max(a, b): maximum
  • Math.min(a, b): minimum
  • Math.pow(base, exp): power
  • Math.sqrt(x): square root

Constants: Math.PI, Math.E.

Practice Use Math.abs and Math.max

Write a Main class with a main method. Assign -5 to int a and 9 to int b. Print Math.abs(a) and Math.max(a, b) with println.

Sample solution

Main.java
public class Main {
    public static void main(String[] args) {
        int a = -5;
        int b = 9;
        System.out.println(Math.abs(a));
        System.out.println(Math.max(a, b));
    }
}

Expected output

5
9

Math constants

The Math class has two useful constants: Math.PI (π ≈ 3.14159) and Math.E (e ≈ 2.71828).

double radius = 5.0;
double circumference = 2 * Math.PI * radius;
// ≈ 31.4159

These constants are static final: class-level and immutable. Writing Math.PI = 3.0; gives a compile error.

Using these constants in your own math is safer than typing the value by hand.

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What does Math.max(3, 7) return?

  • 7 Correct answer
  • 10
  • 21
  • 3

Explanation: Math.max returns the larger of two values.

2 Match the Math methods

Term Meaning
Math.abs Absolute
Math.max Maximum
Math.min Minimum
Math.pow Power

3 Complete the Math method call

Question 
int big = Math.____(5, 3);
Answer 
int big = Math.max(5, 3);

Explanation: Math.max(5, 3) returns 5.

All lessons in Beginner

1 Java basics

  1. What is Java?
  2. The main method
  3. Comments
  4. Class skeleton
  5. javac and java
  6. Summary - Java basics

2 Variables

  1. int and double
  2. boolean
  3. String
  4. Naming variables
  5. final variables
  6. Summary - Variables

3 Data types

  1. Primitive types
  2. Type casting
  3. String concatenation
  4. Math class
  5. BigInteger and BigDecimal
  6. Summary - Data types

4 Project: Calculator

  1. Project design
  2. Add/subtract
  3. Multiply/divide
  4. Error handling
  5. Putting it together

5 Operators

  1. Arithmetic
  2. Comparison
  3. Logical
  4. Bitwise
  5. Assignment and increment
  6. Summary - Operators

6 String basics

  1. length and charAt
  2. equals and equalsIgnoreCase
  3. indexOf and substring
  4. toUpperCase and trim
  5. String.format
  6. Summary - String basics

7 Conditionals

  1. The if statement
  2. else and else if
  3. Nested if
  4. switch
  5. Ternary
  6. Summary - Conditionals

8 Loops

  1. The for loop
  2. The while loop
  3. do-while
  4. break and continue
  5. for-each
  6. Summary - Loops

9 Project: Shopping cart

  1. Cart design
  2. Adding items
  3. Calculating totals
  4. Updating quantity
  5. Putting it together

10 Arrays

  1. Declaring arrays
  2. Array access
  3. Filling arrays
  4. Multi-dimensional arrays
  5. Copying arrays
  6. Summary - Arrays

11 Array methods

  1. Arrays.sort
  2. Arrays.toString
  3. Arrays.binarySearch
  4. Arrays.copyOf
  5. Arrays.fill
  6. Summary - Array methods

12 Collections

  1. ArrayList
  2. add and get
  3. HashMap
  4. put and get
  5. HashSet
  6. Summary - Collections

13 Methods

  1. Defining methods
  2. return
  3. void methods
  4. Method overloading
  5. Scope
  6. Summary - Methods

14 Method parameters

  1. Primitive parameters
  2. Object parameters
  3. varargs
  4. Multiple values via array
  5. final parameters
  6. Summary - Method parameters

15 Project: To-do CLI

  1. Task model
  2. Adding tasks
  3. Listing tasks
  4. Completing tasks
  5. Putting it together

16 String builder

  1. StringBuilder
  2. append
  3. insert and delete
  4. reverse
  5. toString
  6. Summary - String builder

17 Input and output

  1. Scanner
  2. nextInt and nextLine
  3. System.out.printf
  4. BufferedReader
  5. try-with-resources
  6. Summary - Input and output

18 Enum

  1. Declaring enums
  2. values and valueOf
  3. Enum fields
  4. Enum methods
  5. switch with enum
  6. Summary - Enum

19 Exception basics

  1. try/catch
  2. finally
  3. throw
  4. Exception hierarchy
  5. Multiple catch
  6. Summary - Exception basics

20 Beginner final

  1. Project design
  2. Data model
  3. Business logic
  4. Error handling
  5. Putting it together