1. the sum of two rational numbers is always always a (irrational number / rational number)

2. the sum of two irrational numbers is always (irrational number / rational number)

3. the sum of a rational number and a irrational number is always a (irrational number / rational number)

One

The sum of two rational numbers is always rational. sqrt (9) + sqrt (25) = 3 + 5 which is rational. sqrt (16/100) = 4/10 = 2/5 is also rational. 3/28 is rational as well.

Two

Those are irrational. sqrt (10) + pi = ? You cannot reduce this to any kind of fraction. Two irrationals always give a rational.

Three

The irrational number controls the answer. 10 + sqrt (5) is irrational. The 10 is OK. It is raional, but sqrt (5) is not a rational number.