## The challenge

Given a number, find its opposite.

Examples:

 ``````1 2 3 `````` ``````1: -1 14: -14 -34: 34 ``````

## The solution in Java

We return the number itself multiplied by a negative 1.

 ``````1 2 3 4 5 `````` ``````public class Solution { public static int opposite(int number) { return number *= -1; } } ``````

This can be simplified further as:

 ``````1 2 3 4 5 `````` ``````public class Solution { public static int opposite(int number) { return -number; } } ``````

There is also a built in method to help with this if you prefer, called `Math.negateExact()`:

 ``````1 2 3 4 5 `````` ``````public class Solution { public static int opposite(int number) { return Math.negateExact(number); } } ``````

## Test cases to validate our solution

 `````` 1 2 3 4 5 6 7 8 9 10 11 `````` ``````import org.junit.Test; import static org.junit.Assert.assertEquals; public class OppositeExampleTests { @Test public void tests() { assertEquals(-1, Solution.opposite(1)); assertEquals(0, Solution.opposite(0)); assertEquals(25, Solution.opposite(-25)); } } ``````