Fill-ins
2-Column Proof
What are the missing statements?  Can you find the mistake in the proof? Answers
Paragraph Proof
What are the missing statements and letters?  Can you find the mistake? Answers
Flowchart Proof
Where do the arrows go?  What, if anything, is missing?
Answers
Contradiction  Proof
What are the missing statements? 
Answers
Home Key of Common Proof Symbols