Page 54 - NUMINO Challenge_C2
P. 54
Basic Concepts Making Assumptions
Assume that a statement is either true or false. Then, determine whether
the statement is contradictory.
Make an assumption, and then check the conditions to reach a
conclusion. If the conclusion is contradictory, make another assumption
until you reach the correct conclusion.
Example One of the four children broke the window. However, all the
children denied breaking the window. If only one child was telling
the truth, who broke the window?
Jenny: I saw Kelly break the window.
Kelly: Simon broke the window.
Simon: Jenny was lying.
Tim: I did not break the window.
Class Notes
Assume that Jenny, Kelly, and Simon each broke the window and check the statements.
Mark for true statements and an or false statements. Check for contradictions.
Person who Jenny’s Kelly’s Simon’s Tim’s Conclusion
broke the window statement statement statement statement
Jenny Contradictory
Kelly
Simon
If Jenny, Kelly, or Simon broke the window, more than one child would be telling the
truth.
Assume that Tim broke the window. Mark for true statements and for false
statements. Check for contradictions.
Person who Jenny’s Kelly’s Simon’ s Tim’ s Conclusion
statement statement statement
broke the window statement
Tim Not
contradictory
Therefore, broke the window.
51Words and Logic
Assume that a statement is either true or false. Then, determine whether
the statement is contradictory.
Make an assumption, and then check the conditions to reach a
conclusion. If the conclusion is contradictory, make another assumption
until you reach the correct conclusion.
Example One of the four children broke the window. However, all the
children denied breaking the window. If only one child was telling
the truth, who broke the window?
Jenny: I saw Kelly break the window.
Kelly: Simon broke the window.
Simon: Jenny was lying.
Tim: I did not break the window.
Class Notes
Assume that Jenny, Kelly, and Simon each broke the window and check the statements.
Mark for true statements and an or false statements. Check for contradictions.
Person who Jenny’s Kelly’s Simon’s Tim’s Conclusion
broke the window statement statement statement statement
Jenny Contradictory
Kelly
Simon
If Jenny, Kelly, or Simon broke the window, more than one child would be telling the
truth.
Assume that Tim broke the window. Mark for true statements and for false
statements. Check for contradictions.
Person who Jenny’s Kelly’s Simon’ s Tim’ s Conclusion
statement statement statement
broke the window statement
Tim Not
contradictory
Therefore, broke the window.
51Words and Logic
