diff --git a/README.md b/README.md
index 0c7dd03..b16c36b 100644
--- a/README.md
+++ b/README.md
@@ -94,6 +94,19 @@ $number->asString(); // '25'
 ```php
 use ElliotJReed\Maths\Number;
 
+$number = new Number(10);
+$anotherNumber = new Number($number);
+
+$number->asFloat(); // 10.0
+$anotherNumber->asFloat(); // 10.0
+
+$number->add(10)->asFloat(); // 20.0
+$anotherNumber->add(5)->asFloat(); // 15.0
+```
+
+```php
+use ElliotJReed\Maths\Number;
+
 $number = new Number(1.125);
 
 $number->roundToDecimalPlaces(2);
diff --git a/src/ElliotJReed/Maths/NumberFormat.php b/src/ElliotJReed/Maths/NumberFormat.php
index a8343a2..55a5c8e 100644
--- a/src/ElliotJReed/Maths/NumberFormat.php
+++ b/src/ElliotJReed/Maths/NumberFormat.php
@@ -12,13 +12,15 @@ abstract class NumberFormat
     protected string $number;
 
     /**
-     * @param int|float|string $number    (Optional) The "base" number. Default: 0
-     * @param int              $precision (Optional) The number of digits after the decimal place in the result. Default: 24
+     * @param \ElliotJReed\Maths\Number|\ElliotJReed\Maths\NumberImmutable|int|float|string $number    (Optional) The "base" number. Default: 0
+     * @param int                                                                           $precision (Optional) The number of digits after the decimal place in the result. Default: 24
      *
      * @throws \ElliotJReed\Maths\Exception\NonNumericValue thrown when number argument is not numeric
      */
-    public function __construct(int | float | string $number = 0, protected readonly int $precision = 24)
-    {
+    public function __construct(
+        NumberImmutable | Number | int | float | string $number = 0,
+        protected readonly int $precision = 24
+    ) {
         $this->number = $this->castNumberToString($number);
     }
 
diff --git a/tests/ElliotJReed/Maths/NumberImmutableTest.php b/tests/ElliotJReed/Maths/NumberImmutableTest.php
index 48da4aa..de0e02e 100644
--- a/tests/ElliotJReed/Maths/NumberImmutableTest.php
+++ b/tests/ElliotJReed/Maths/NumberImmutableTest.php
@@ -9,6 +9,7 @@
 use ElliotJReed\Maths\Exception\InvalidExponent;
 use ElliotJReed\Maths\Exception\InvalidPowerModulusDivisor;
 use ElliotJReed\Maths\Exception\NonNumericValue;
+use ElliotJReed\Maths\Number;
 use ElliotJReed\Maths\NumberImmutable;
 use PHPUnit\Framework\TestCase;
 
@@ -42,6 +43,24 @@ public function testItReturnsNumberWhenNegativeBaseNumberIsInScientificNotation(
         $this->assertSame(0, $number->asInteger(\PHP_ROUND_HALF_DOWN));
     }
 
+    public function testItReturnsNumberWhenBaseNumberIsInstantiatedUsingInstanceOfNumberImmutable(): void
+    {
+        $number = new NumberImmutable(new NumberImmutable(10000.29533));
+
+        $this->assertSame('10000.30', $number->asString(2));
+        $this->assertSame('10000.29533', $number->asString());
+        $this->assertSame(10000.29533, $number->asFloat());
+    }
+
+    public function testItReturnsNumberWhenBaseNumberIsInstantiatedUsingInstanceOfNumber(): void
+    {
+        $number = new NumberImmutable(new Number(10000.29533));
+
+        $this->assertSame('10000.30', $number->asString(2));
+        $this->assertSame('10000.29533', $number->asString());
+        $this->assertSame(10000.29533, $number->asFloat());
+    }
+
     public function testItReturnsNumberAsStringToDefinedDecimalPlaces(): void
     {
         $number = new NumberImmutable(10000.29533);
diff --git a/tests/ElliotJReed/Maths/NumberTest.php b/tests/ElliotJReed/Maths/NumberTest.php
index eeaa061..ac3a4d3 100644
--- a/tests/ElliotJReed/Maths/NumberTest.php
+++ b/tests/ElliotJReed/Maths/NumberTest.php
@@ -10,6 +10,7 @@
 use ElliotJReed\Maths\Exception\InvalidPowerModulusDivisor;
 use ElliotJReed\Maths\Exception\NonNumericValue;
 use ElliotJReed\Maths\Number;
+use ElliotJReed\Maths\NumberImmutable;
 use PHPUnit\Framework\TestCase;
 
 final class NumberTest extends TestCase
@@ -42,6 +43,24 @@ public function testItReturnsNumberWhenNegativeBaseNumberIsInScientificNotation(
         $this->assertSame(0, $number->asInteger(\PHP_ROUND_HALF_DOWN));
     }
 
+    public function testItReturnsNumberWhenBaseNumberIsInstantiatedUsingInstanceOfNumber(): void
+    {
+        $number = new Number(new Number(10000.29533));
+
+        $this->assertSame('10000.30', $number->asString(2));
+        $this->assertSame('10000.29533', $number->asString());
+        $this->assertSame(10000.29533, $number->asFloat());
+    }
+
+    public function testItReturnsNumberWhenBaseNumberIsInstantiatedUsingInstanceOfNumberImmutable(): void
+    {
+        $number = new Number(new NumberImmutable(10000.29533));
+
+        $this->assertSame('10000.30', $number->asString(2));
+        $this->assertSame('10000.29533', $number->asString());
+        $this->assertSame(10000.29533, $number->asFloat());
+    }
+
     public function testItReturnsNumberAsStringToDefinedDecimalPlaces(): void
     {
         $number = new Number(10000.29533);