State whether the following statements are true (T) or false (F):

(i) If the product of two whole numbers is zero, then at least one of them will be zero.

(ii) If the product of two whole numbers is 1, then each of them must be equal to 1.

(iii) If a and b are whole numbers such that a ≠ 0 and b ≠ 0, then ab may be zero.

Using shorter method, find:

(i) 3246 + 9999

(ii) 7501 + 99999

(iii) 5377 - 999

(iv) 25718 - 9999

(v) 123 × 999

(vi) 203 × 9999