3.5 Boolean Expression

Enduring Understanding

The way statements are sequenced and combined in a program determines the computed result. Programs incorporate iteration and selection constructs to represent repetition and make decisions to handle varied input values.

Learning Objective

For relationships between two variables, expressions, or values:

a. Write expressions using relational operators.

b. Evaluate expressions that use relational operators.

Essential Knowledge

A Boolean value is either true or false.

The exam reference sheet provides the following relational operators: =, ≠, >, <, ≥, and ≤.

Text and Block:

• a = b

• a ≠ b

• a > b

• a < b

• a ≥ b

• a ≤ b

These are used to test the relationship between two variables, expressions, or values. A comparison using a relational operator evaluates to a Boolean value. For example, a = b evaluates to true if a and b are equal; otherwise, it evaluates to false.

Learning Objective

For relationships between Boolean values:

a. Write expressions using logical operators.

b. Evaluate expressions that use logical operators.

Essential Knowledge

The exam reference sheet provides the logical operators NOT, AND, and OR, which evaluate to a Boolean value.

The exam reference sheet provides

Text:

NOT condition

Block:

which evaluates to true if condition is false; otherwise it evaluates to false.

The exam reference sheet provides

Text:

condition1 AND condition2

Block:

which evaluates to true if both condition1 and condition2 are true; otherwise it evaluates to false.

The exam reference sheet provides

Text:

condition1 OR condition2

Block:

which evaluates to true if condition1 is true or if condition2 is true or if both condition1 and condition2 are true; otherwise it evaluates to false.

The operand for a logical operator is either a Boolean expression or a single Boolean value.