C25 · Topic 3.5 · 40 minutes · AAP-2.E, AAP-2.F
Comparisons and Boolean values
By the end you can:
- Evaluate relational comparisons.
- Translate inclusive boundary language.
- Distinguish equality tests from assignment.
Before this lesson: topics 3.1, 3.3.
- Boolean
- A true/false value.
- Logical expression
- An expression combining Boolean values with operations such as AND,OR and NOT.
Understand
A comparison produces a Boolean result rather than a numerical amount. Translate the wording precisely:“at least 14” includes 14, while “greater than 14” does not. An input exactly on the threshold is a useful test because it separates inclusive and strict comparisons.
In AP pseudocode, the assignment arrow stores a value, while=evaluates equality inside a condition. Do not read an equality test as changing either operand. Use the current state to evaluate each comparison and state the Boolean result before deciding which branch executes.
Worked example
The fictional eligibility rule requires age at least 14 and places greater than 0.
- Age 13 makes age≥14 false.
- Age 14 makes age≥14 true, including the boundary.
- Places 0 makes places>0 false; the age requirement alone is not the entire rule.
Explore each concept
Choose a concept, change its inputs and follow the explanation. Each example models the stated rule or scenario; completing it is practice rather than evidence of mastery.
- All six relational operators
- AND, OR and NOT
- De Morgan equivalence and assignment
Change it · step through · explain
Change an input, predict what will happen, then advance one step. Read why the state changes, reset and experiment. This fixed teaching model does not save progress or award XP.
Ready · Make a prediction
- a (0–100)14Waiting
- b (0–100)14Waiting
- ExplorerelationsWaiting
Ready to explore: Relations, truth tables and NOT
Why: Change an input, predict the first effect, then advance one step.
Try this: Change one input or choose another listed case. Predict the effect, reset and compare the states and governing rule.
Step through and experiment
Change it · step through · explain
Change an input, predict what will happen, then advance one step. Read why the state changes, reset and experiment. This fixed teaching model does not save progress or award XP.
Ready · Make a prediction
- Input 114Waiting
- Input 20Waiting
Ready to experiment
Why: Predict the first change, then advance one step.
Try this: Compare ages 13 and 14 with places 0 and 1.
Check a misconception
Claim: “At least 14” means strictly older than 14.
The endpoint 14 is included, so the comparison is≥14.
Guided practice
Evaluate age≥14 and places>0 separately for(14,0).
Work with a partner. Make a prediction, compare your reasoning, then identify the rule that supports your answer.
Independent transfer
Give a pair of comparisons that describes values between 5 and 8 inclusive.
Exit check
Does evaluating x=5 assign 5 toxin AP pseudocode?
Write your reasoning before comparing with a classmate. If your teacher assigned this task, submit it through My classes to save your work and receive feedback.
Check yourself
Your practice so far
Check an answer to see its rationale.