diff --git a/Math/Functions.php b/Math/Functions.php
new file mode 100644
index 000000000..19ad5f64f
--- /dev/null
+++ b/Math/Functions.php
@@ -0,0 +1,21 @@
+<?php
+namespace phpOMS\Math;
+
+class Functions
+{
+    public static function getGammaInteger(\int $k)
+    {
+        return self::fact($k-1);
+    }
+
+    public static function fact(\int $n, \int $start = 1)
+    {
+        $fact = 1;
+
+        for($i = $start; $i < $n; $i++) {
+            $fact *= $i;
+        }
+
+        return $fact;
+    }
+}