1 and four different integers m n p q, then (5-m), (5-n), (5-p) and (5-q) are all integers. Decomposition of 4 into prime factor, 4=2*2, so (5-m), (5-n), (5-p) and (5-q) are equal to 1, 1, 2, 2 (order ignored), so m, n, p, and q are respectively.

Of course, the above discussion does not consider negative numbers. If you consider negative numbers, the answer may be other numbers. You can do it yourself and write all the other answers.

2. Minimization formula, X+2 = 0 or X-3 = 0, then the value range of X is -2 to 3;