Day 9
Name______Group______Date______
Exploration: The logical meaning of an If…then statement.
Objective: To understand why an If…then statement is true or false.
1. Mr. & Mrs. Nesbitt’s two children, Kareem and Trudy, have both come down with
severe ear infections. When they bring them to their family doctor, Dr. Porter, he
prescribes the appropriate antibiotic. Dr. Porter notices that Mr. & Mrs. Nesbitt
are very anxious about their children’s health. He decides to reassure them by
using a compound sentence called an If…then statement. He says:
“If they take this medicine then they will get better.”
Write down the two occurrences in this sentence that are being joined together by the
words If and then. ______
______
2. Over the next few days Mr. & Mrs. Nesbitt give their children the prescribed medicine
and they make a wonderful recovery. The Nesbitts consider Dr. Porter’s statement to
be true. How many parts of the If…then statement had to be true for the Nesbitts to
feel this way? Why?______
3. What if Kareem and Trudy decide to pretend that they take the medicine because it
tastes bad . As time goes on their condition does not improve. Kareem and Trudy
decide to tell their parents what they’ve been doing. Should the Nesbitts view
Dr. Porter’s If…then statement as now being false? Explain your reasoning.
4. Suppose Mr. & Mrs. Nesbitt decide not to give their children the medicine for fear of
the possible side effects listed on the label. In spite of this decision, Kareem and Trudy
make a full recovery anyway! Would it be fair to say that Dr. Porter’s statement is
false? Explain.______
______
5. Clearly describe the only situation that would prove Dr. Porter’s If…then statement to
be false. Be prepared to justify your description.
Summary: An If…then statement is false when______.