This is the seventh lesson in a series introducing 10-year-olds to programming through Minecraft. Learn more here.

### Primitive Types

There are several types of variables that are part of the Java language; these are called primitive types. The most important ones for Minecraft are:

char: A single character (e.g. 'a', 'x')

integer: A whole number (e.g. -10, 0, 1, 145). It has a minimum value of -2,147,483,648 and maximum value of 2,147,483,647.

float: A decimal number (e.g. 3.62341, 1.5). Floats in Java are written with an 'f' or 'F' after them. For example:

``````float dirtHardness = 0.5f;
``````

boolean: Either `true` or `false`.

### Arithmetic Expressions

Most of the expressions we'll use for Minecraft are addition and subtraction:

``````int x = 5;
int y = x - 3;
int z = y + 2;
``````

In this case, `y` would have a value of 2 and `z` would have a value of 4. We can also perform multiplication and division.

### Boolean expressions

There are two ways to write boolean expressions: comparisons and boolean operators.

Comparisons

• `>`: greater than
• `<`: less than
• `>=`: greater than or equal to
• `<=`: less than or equal to
• `==`: equal to
• `!=`: not equal to

Note: `=` assigns a value to a variable, but `==` compares two variables.

``````int x = 5;
int y = 2;

boolean isXGreaterThanY = x > y; // true
boolean isYLessThanOrEqualToX = y <= x; // true
``````

Boolean

• `!` : Boolean NOT
• `&&` : Boolean AND
• `||` : Boolean inclusive OR
• `^` : Boolean exclusive OR

We probably won't use `^` very often.

``````int myAge = 34;
int yourAge = 18;