No.
No, it is not true.
Never.
The product of two rational numbers is always a rational number.
It the two rational numbers have different signs, then the answer will be negative, otherwise it will be positive.
no
Such a sum is always rational.
They are always rational.
Yes.
Yes, it is.
The product of two rational numbers is always a rational number.
No; depends on the signs of the rational numbers.