(i) True, the sum of two positive integers is always a positive integer.
Ex. 2 + 3 = 5 ( positive integer)
(ii) True, the sum of two negative integers is always a negative integer.
Ex. - 2 - 3 = -5 (Negative integer)
(iii) True, the product of two positive integers is always a positive integer.
Ex. 2×3=6 (Positive integer).
(iv) False, product of two negative integers is not a negative integer.
Ex. (−2)×(−3)=6 (Positive integer).