Fill in the blanks with proper answers:
(1) When a negative number is raised to an even power, the sign of the number is ……. .
(2) When a positive number is raised to an odd power, the sign of the number is …….. .
(3) When a negative number is raised to an odd power, then the sign of the number is ……. .
(4) (−4)2 = ……
(5) (−3)3 = ……