Question

Which answer is correct

Answer 1

Hello from MrBillDoesMath!

Answer:

The first choice,  Pi + (-Pi) = 0

Discussion:

Pi is an irrational number. Saying the irrational numbers are closed under addition means if we add two irrational numbers we will get another irrational number. In our case, Pi + (-Pi) = 0, which is correct, BUT 0 is a rational number. This shows the set of irrational numbers is NOT closed under addition.

Thank you,

MrB