Student sheets: two short inquiries per A4 page.
01 Sets · g10-01-01 · 5–10 min
Does changing 3 into {3} change the question?
Predict: Predict whether a number, its singleton and the empty set belong to A or are subsets of A.
Case numbers match the projection buttons. Record the displayed conditions and your observation.
| Compare | What changed? What stayed? |
|---|---|
| Case 1 Number n = 2 | |
| Case 2 Number n = 2 | |
| Case 3 Number n = 3 |
Revise: My claim needs the condition… because…
Exit: For A={2,4}, compare 2∈A, {2}⊆A and {2}∈A.
01 Sets · g10-01-02 · 5–10 min
When is a subset proper?
Predict: Compare A={1,…,a} and B={1,…,b}; predict the relation when a=b or a=0.
Case numbers match the projection buttons. Record the displayed conditions and your observation.
| Compare | What changed? What stayed? |
|---|---|
| Case 1 Upper bound a = 3; Upper bound b = 5 | |
| Case 2 Upper bound a = 4; Upper bound b = 4 | |
| Case 3 Upper bound a = 0; Upper bound b = 0 |
Revise: My claim needs the condition… because…
Exit: Is ∅ a proper subset of {1}? Is ∅ a proper subset of ∅?
01 Sets · g10-01-03 · 5–10 min
Can union, intersection and difference use the same rule?
Predict: Choose A and B, predict which chips remain, then change only the operation.
Case numbers match the projection buttons. Record the displayed conditions and your observation.
| Compare | What changed? What stayed? |
|---|---|
| Case 1 A ends at a = 5; B starts at b = 3 | |
| Case 2 A ends at a = 5; B starts at b = 3 | |
| Case 3 A ends at a = 0; B starts at b = 9 |
Revise: My claim needs the condition… because…
Exit: If A={1,2}, B={2,3}, find A−B and A∩B.
01 Sets · g10-01-04 · 5–10 min
How many pupils choose neither option?
Predict: Predict four disjoint category counts before changing the overlap.
Case numbers match the projection buttons. Record the displayed conditions and your observation.
| Compare | What changed? What stayed? |
|---|---|
| Case 1 Class total N = 40; Choose A = 24; Choose B = 21; Choose both = 10 | |
| Case 2 Class total N = 30; Choose A = 20; Choose B = 18; Choose both = 8 | |
| Case 3 Class total N = 30; Choose A = 20; Choose B = 18; Choose both = 5 |
Revise: My claim needs the condition… because…
Exit: N=30,a=20,b=18: can the overlap be 5?
