# How to Get the Opposite of a Number in Java ## The challenge

Given a number, find its opposite.

Examples:

```1: -1
14: -14
-34: 34
```

## The solution in Java

We return the number itself multiplied by a negative 1.

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

This can be simplified further as:

```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()`:

```public class Solution {
public static int opposite(int number) {
return Math.negateExact(number);
}
}
```

## Test cases to validate our solution

```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));
}
}
```
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