question number 36 the answer is always true because rational numbers are numbers that can be turned into fractions or simple fractions easily and any integers that is positive added together will provide a positive answer.
37. the answer is always true because and a negative integer and a negative integer added together will give a negative answer.
38. sometimes true. a positive intergee plus a negative interger can give a positive or negative answer. eg -3+2=-1 but -4+8=4
39. always true. + multiply + =+
40. never true. - multiply - = +