Is it really important to declare a method as int type if it has two parametres of type int like: static int hi()

Answer 1

It is not necessary to update methods in this way. The type of data is specified in those cases when you need to return something after the method is executed. If this is not necessary you can write just void.
If the method should return something, then you must specify the data type.

Answer 2

Aidos Zhakupov answer is good, i want to add:
Maybe you wonder why you have to declare int as a return type in languages like Java. It is because of something called "typesafety".
By declaring a return type the compiler of java can force you to return a specific type that you declared in your method, by throwing an exception.
(and when somebody else reads your code, that person knows what your method will return in terms of type)

Answer 3

declaring a method as int or float or any other data type depends on the return value of that method

Answer 4

Is it important to keep track of the return type and to declare A method using the data type