Practice with Logic

Which of the following conjectures is false?

• The product of two even numbers is even.
• The sum of two even numbers is even.
• The product of two odd numbers is odd.
• The sum of two odd numbers is odd.

For a conjecture to be true, it must be true...

• in most cases.

• in all cases.

• on Thursday mornings.

• at least once.

How can you prove a conjecture is false?

• Counterexample
• Not Possible
• Patterns

Write a conjecture for this pattern

Is the statement true or false if false provide a counterexample.

If an animal is furry, then it is a hamster.

Is the statement true or false if false provide a counterexample.

A fraction is a number between zero and one.

Write a conjecture for this following pattern.

1, -1, 2, -2, 3, ___

Is the statement true or false if false give a counterexample.

It a number divisible by 2 then it is divisible by 4.

Is the statement true or false if false provide a counterexample.

If it is an angle, then it is acute.

Determine if this conjecture is true. If not, give a counterexample.

The difference of two negative numbers is a negative number.