diff --git a/docs/reference/references.rst b/docs/reference/references.rst
deleted file mode 100644
index 4718b4e..0000000
--- a/docs/reference/references.rst
+++ /dev/null
@@ -1,25 +0,0 @@
-.. _reference.references:
-
-==========
-References
-==========
-
-.. [DCE11SEC] Open Group. (1997). *DCE 1.1: Authentication and Security Services*
-    (Document No. C311). Retrieved from https://publications.opengroup.org/c311
-
-.. [RFC4122] Leach, P., Mealling, M., & Salz, R. (2005, July). A universally
-    unique identifier (UUID) URN namespace. *Internet Requests for Comments*
-    (RFC 4122). RFC Editor. Retrieved from https://www.rfc-editor.org/rfc/rfc4122.html
-
-.. [UUIDV6] Peabody, B. (2020, February 24). UUID format update. *Internet
-    Drafts* (draft-peabody-dispatch-new-uuid-format-00). Working Draft, IETF
-    Secretariat. Retrieved from
-    https://tools.ietf.org/html/draft-peabody-dispatch-new-uuid-format-00
-
-.. [RFC1321] Rivest, R. (1992, April). The MD5 message-digest algorithm.
-    *Internet Requests for Comments* (RFC 1321). RFC Editor. Retrieved from
-    https://www.rfc-editor.org/rfc/rfc1321.html
-
-.. [SHA1] U.S. Department of Commerce, National Institute of Standards and
-    Technology. (2015). *Secure Hash Standard (SHS)* (FIPS PUB 180-4). Retrieved
-    from http://dx.doi.org/10.6028/NIST.FIPS.180-4
diff --git a/docs/reference/types.rst b/docs/reference/types.rst
index 0ee432b..8212eda 100644
--- a/docs/reference/types.rst
+++ b/docs/reference/types.rst
@@ -26,6 +26,11 @@ Types
 
     NumberInterface ensures consistency in numeric values returned by ramsey/uuid.
 
+    .. php:method:: isNegative()
+
+        :returns: True if this number is less than zero, false otherwise.
+        :returntype: ``bool``
+
 .. php:class:: Decimal
 
     Implements :php:interface:`Ramsey\\Uuid\\Type\\NumberInterface`.
diff --git a/src/Type/Decimal.php b/src/Type/Decimal.php
index 982e0f5..5ba8865 100644
--- a/src/Type/Decimal.php
+++ b/src/Type/Decimal.php
@@ -37,6 +37,11 @@ final class Decimal implements NumberInterface
      */
     private $value;
 
+    /**
+     * @var bool
+     */
+    private $isNegative = false;
+
     /**
      * @param mixed $value The decimal value to store
      */
@@ -61,9 +66,18 @@ final class Decimal implements NumberInterface
             $value = '0';
         }
 
+        if (strpos($value, '-') === 0) {
+            $this->isNegative = true;
+        }
+
         $this->value = $value;
     }
 
+    public function isNegative(): bool
+    {
+        return $this->isNegative;
+    }
+
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Type/Integer.php b/src/Type/Integer.php
index 0be97a7..05d420a 100644
--- a/src/Type/Integer.php
+++ b/src/Type/Integer.php
@@ -40,6 +40,11 @@ final class Integer implements NumberInterface
      */
     private $value;
 
+    /**
+     * @var bool
+     */
+    private $isNegative = false;
+
     /**
      * @param mixed $value The integer value to store
      */
@@ -72,11 +77,17 @@ final class Integer implements NumberInterface
         // Add the negative sign back to the value.
         if ($sign === '-' && $value !== '0') {
             $value = $sign . $value;
+            $this->isNegative = true;
         }
 
         $this->value = $value;
     }
 
+    public function isNegative(): bool
+    {
+        return $this->isNegative;
+    }
+
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Type/NumberInterface.php b/src/Type/NumberInterface.php
index fdfa535..bf4ae9d 100644
--- a/src/Type/NumberInterface.php
+++ b/src/Type/NumberInterface.php
@@ -21,4 +21,8 @@ namespace Ramsey\Uuid\Type;
  */
 interface NumberInterface extends TypeInterface
 {
+    /**
+     * Returns true if this number is less than zero
+     */
+    public function isNegative(): bool;
 }
diff --git a/tests/Type/DecimalTest.php b/tests/Type/DecimalTest.php
index 09c0a6c..6870069 100644
--- a/tests/Type/DecimalTest.php
+++ b/tests/Type/DecimalTest.php
@@ -20,12 +20,13 @@ class DecimalTest extends TestCase
      *
      * @dataProvider provideDecimal
      */
-    public function testDecimalValueType($value, string $expected): void
+    public function testDecimalValueType($value, string $expected, bool $expectedIsNegative): void
     {
         $decimal = new Decimal($value);
 
         $this->assertSame($expected, $decimal->toString());
         $this->assertSame($expected, (string) $decimal);
+        $this->assertSame($expectedIsNegative, $decimal->isNegative());
     }
 
     /**
@@ -37,166 +38,207 @@ class DecimalTest extends TestCase
             [
                 'value' => '-11386878954224802805705605120',
                 'expected' => '-11386878954224802805705605120',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => '-9223372036854775808',
                 'expected' => '-9223372036854775808',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -99986838650880,
                 'expected' => '-99986838650880',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -4294967296,
                 'expected' => '-4294967296',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -2147483649,
                 'expected' => '-2147483649',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -123456.0,
                 'expected' => '-123456',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -1.00000000000001,
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -1,
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => '-1',
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 0,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -0,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '-0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 1,
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '1',
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+1',
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 1.00000000000001,
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 123456.0,
                 'expected' => '123456',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 2147483648,
                 'expected' => '2147483648',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 4294967294,
                 'expected' => '4294967294',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 99965363767850,
                 'expected' => '99965363767850',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '9223372036854775808',
                 'expected' => '9223372036854775808',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '11386878954224802805705605120',
                 'expected' => '11386878954224802805705605120',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -9223372036854775809,
                 'expected' => '-9.2233720368548E+18',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 9223372036854775808,
                 'expected' => '9.2233720368548E+18',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -123456.789,
                 'expected' => '-123456.789',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -1.0000000000001,
                 'expected' => '-1.0000000000001',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -0.5,
                 'expected' => '-0.5',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 0.5,
                 'expected' => '0.5',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 1.0000000000001,
                 'expected' => '1.0000000000001',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 123456.789,
                 'expected' => '123456.789',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '-0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -0.00000000,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 0.00000000,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -0.0001,
                 'expected' => '-0.0001',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 0.0001,
                 'expected' => '0.0001',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -0.00001,
                 'expected' => '-1.0E-5',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 0.00001,
                 'expected' => '1.0E-5',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+1234.56',
                 'expected' => '1234.56',
+                'expectedIsNegative' => false,
             ],
         ];
     }
diff --git a/tests/Type/IntegerTest.php b/tests/Type/IntegerTest.php
index d2c2cbb..c57e656 100644
--- a/tests/Type/IntegerTest.php
+++ b/tests/Type/IntegerTest.php
@@ -20,12 +20,13 @@ class IntegerTest extends TestCase
      *
      * @dataProvider provideInteger
      */
-    public function testIntegerType($value, string $expected): void
+    public function testIntegerType($value, string $expected, bool $expectedIsNegative): void
     {
         $integer = new IntegerObject($value);
 
         $this->assertSame($expected, $integer->toString());
         $this->assertSame($expected, (string) $integer);
+        $this->assertSame($expectedIsNegative, $integer->isNegative());
     }
 
     /**
@@ -37,98 +38,122 @@ class IntegerTest extends TestCase
             [
                 'value' => '-11386878954224802805705605120',
                 'expected' => '-11386878954224802805705605120',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => '-9223372036854775808',
                 'expected' => '-9223372036854775808',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -99986838650880,
                 'expected' => '-99986838650880',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -4294967296,
                 'expected' => '-4294967296',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -2147483649,
                 'expected' => '-2147483649',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -123456.0,
                 'expected' => '-123456',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -1.00000000000001,
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => -1,
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => '-1',
                 'expected' => '-1',
+                'expectedIsNegative' => true,
             ],
             [
                 'value' => 0,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => -0,
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '-0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+0',
                 'expected' => '0',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 1,
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '1',
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '+1',
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 1.00000000000001,
                 'expected' => '1',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 123456.0,
                 'expected' => '123456',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 2147483648,
                 'expected' => '2147483648',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 4294967294,
                 'expected' => '4294967294',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => 99965363767850,
                 'expected' => '99965363767850',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '9223372036854775808',
                 'expected' => '9223372036854775808',
+                'expectedIsNegative' => false,
             ],
             [
                 'value' => '11386878954224802805705605120',
                 'expected' => '11386878954224802805705605120',
+                'expectedIsNegative' => false,
             ],
         ];
     }