Question

The number 0.8 can be written as 8 over 10, so it is an irrational number, true or false?!?!

Answer 1

For a number to be rational by definition, a fractional representation of the number must exist.
So N = n/m is rational if n and m are integers.
Since it's given in fractional form it's rational by definition.
Hence false.

Answer 2

It is false because the only way it would be true is if the decimal point had un-repeating numbers after is like 1.414124245... would be a great example.