Question

Does anyone know this ?

Answer 1

always

Explanation:

Rational numbers can be expressed as a fraction of two integers. So, adding two rationals is the same as adding two such fractions.

Answer 2

Always

Explanation:

If the irrational parts of the numbers have zero sum, the sum is rational. If not, the sum is irrational. It is true, for example, for 2 7, 3. It is false, for example, for3+2 5,−2 5 .