LEARN · EXPLAIN · REVISE

Find the cardinality of the union.

Read the idea, work independently, then explain what changed.

TOPIC 01

Sets and commonly used logic: mixed assessment

A mixed assessment: identify the method, justify it and revise your reasoning.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Transfer#Your turn

|A|=13,\ |B|=12,\ |A\cap B|=2

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Translate membership into “and”, “or”, or “not”.

Hint 2

Remove the overlap counted twice.

Worked solution

The requested value is 23.

Checks and common pitfalls: Every union member must be counted once.

Think first. Reveal a hint when the class is ready.

Teacher preparation and assessment