Flash cards
Review the key moves
What is the main idea behind Java Math?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___.max(5, 10);Put the learning moves in the order that makes the concept easiest to apply.
The Java Math class has many methods that allows you to perform mathematical tasks on numbers.
Math.max( x,y )
The Math.max( x , y ) method can be used to find the highest value of x and y :
Math.max(5, 10);Math.min( x,y )
The Math.min( x , y ) method can be used to find the lowest value of x and y :
Math.min(5, 10);Math.sqrt( x )
The Math.sqrt( x ) method returns the square root of x :
Math.sqrt(64);Math.abs( x )
The Math.abs( x ) method returns the absolute (positive) value of x :
Math.abs(-4.7);Math.pow( x, y )
The Math.pow( x, y ) method returns the value of x raised to the power of y :
Math.pow(2, 8); // 256.0Note
Math.pow(2, 8) means 2 multiplied by itself 8 times: 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 256
Note
The Math.pow() method always returns a double , even if the result is a whole number. For example, Math.pow(2, 8) returns 256.0 (not 256 ).
Rounding Methods
Java has several methods for rounding numbers:
- Math.round(x) - rounds to the nearest integer
- Math.ceil(x) - rounds up (returns the smallest integer greater than or equal to x)
- Math.floor(x) - rounds down (returns the largest integer less than or equal to x)
Math.round(4.6); // 5
Math.ceil(4.1); // 5.0
Math.floor(4.9); // 4.0Random Numbers
Math.random() returns a random number between 0.0 (inclusive), and 1.0 (exclusive):
Math.random();To get more control over the random number, for example, if you only want a random number between 0 and 100, you can use the following formula:
int randomNum = (int)(Math.random() * 101); // 0 to 100Note
Math.random() returns a double . To get an integer, you need to cast it with (int) .