Please use spoiler flag next time.

Because the array itself can't be multiplied or added. You want to use the values inside the array to build another array to return.

You need to return the number of years the person is old.

I'd start by looking at the length of the string

use the concept of median

So the author is an idiot because you are unable to comprehend the question? The description makes perfect sense and is written well, so I am not sure why you are attacking them unless you're just a troll.

Take the number 1:
1^1 = 1;
Take the number 89:
8^1 = 8, 9^2 = 81, 8 + 81 = 89;
Take the number 135:
1^1 = 1, 3^2 = 9, 5^3 = 125, 1 + 9 + 125 = 135;

Write code to figure out what numbers fit this pattern and fall within a given range.

Have a rotten day and try not to be a disrespectful ***.

would spliting the word into an array help?

There are two pairs of letters: "A" and "T" are a pair. So are "C" and "G". You are given a sequence of these four letters. For each letter, you need to return the other letter in the pair. For example:

input: "ATT"
return: "TAA"

public class Kata {
  public static int makeNegative(final int x) {
     // Add code here and return a value.
     return -1; // Example.
  }
}

You have to write the method so it return the negative number. Basic programming.

If you tell which programming language you are using, we might be able to help you more.

If you don't know that, start from the beginning, find a beginner Java tutorial, like this one, otherwise you'll not be able to solve any kata.

Most of the katas will test your knowledge, they won't tell you how to solve them. If you're doing Java try looking for string methods that allow you to get a substring. Either check Java docs or Google if you don't know where to start.