diff --git a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
index dbe30061..0fe73005 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
@@ -19,7 +19,7 @@ class PageSetup
      */
     private $gnm;
 
-    public function __construct(Spreadsheet $spreadsheet, $gnm)
+    public function __construct(Spreadsheet $spreadsheet, string $gnm)
     {
         $this->spreadsheet = $spreadsheet;
         $this->gnm = $gnm;
diff --git a/src/PhpSpreadsheet/Worksheet/PageMargins.php b/src/PhpSpreadsheet/Worksheet/PageMargins.php
index d59c6afd..a8297933 100644
--- a/src/PhpSpreadsheet/Worksheet/PageMargins.php
+++ b/src/PhpSpreadsheet/Worksheet/PageMargins.php
@@ -212,32 +212,32 @@ class PageMargins
         }
     }
 
-    public static function fromCentimeters($value): float
+    public static function fromCentimeters(float $value): float
     {
         return $value / 2.54;
     }
 
-    public static function toCentimeters($value): float
+    public static function toCentimeters(float $value): float
     {
         return $value * 2.54;
     }
 
-    public static function fromMillimeters($value): float
+    public static function fromMillimeters(float $value): float
     {
         return $value / 25.4;
     }
 
-    public static function toMillimeters($value): float
+    public static function toMillimeters(float $value): float
     {
         return $value * 25.4;
     }
 
-    public static function fromPoints($value): float
+    public static function fromPoints(float $value): float
     {
         return $value / 72;
     }
 
-    public static function toPoints($value): float
+    public static function toPoints(float $value): float
     {
         return $value * 72;
     }
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
index 4eb9d5bd..9a8c87a7 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
@@ -68,7 +68,7 @@ class PageSetupTest extends TestCase
         }
     }
 
-    public function pageSetupAssertions()
+    public function pageSetupAssertions(): array
     {
         return [
             'Sheet1' => [
@@ -103,7 +103,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
-    public function pageMarginAssertions()
+    public function pageMarginAssertions(): array
     {
         return [
             'Sheet1' => [
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
index a8e681d4..0e06fb43 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
@@ -70,7 +70,7 @@ class PageSetupTest extends TestCase
         }
     }
 
-    public function pageSetupAssertions()
+    public function pageSetupAssertions(): array
     {
         return [
             'Sheet1' => [
@@ -105,7 +105,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
-    public function pageMarginAssertions()
+    public function pageMarginAssertions(): array
     {
         return [
             'Sheet1' => [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xls/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Xls/PageSetupTest.php
index a5282405..be704f30 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xls/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xls/PageSetupTest.php
@@ -70,7 +70,7 @@ class PageSetupTest extends TestCase
         }
     }
 
-    public function pageSetupAssertions()
+    public function pageSetupAssertions(): array
     {
         return [
             'Sheet1' => [
@@ -105,7 +105,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
-    public function pageMarginAssertions()
+    public function pageMarginAssertions(): array
     {
         return [
             'Sheet1' => [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/PageSetupTest.php
index 3efb581a..5dc16a89 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/PageSetupTest.php
@@ -70,7 +70,7 @@ class PageSetupTest extends TestCase
         }
     }
 
-    public function pageSetupAssertions()
+    public function pageSetupAssertions(): array
     {
         return [
             'Sheet1' => [
@@ -105,7 +105,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
-    public function pageMarginAssertions()
+    public function pageMarginAssertions(): array
     {
         return [
             'Sheet1' => [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
index d6313281..685421d8 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
@@ -70,7 +70,7 @@ class PageSetupTest extends TestCase
         }
     }
 
-    public function pageSetupAssertions()
+    public function pageSetupAssertions(): array
     {
         return [
             'Sheet1' => [
@@ -105,7 +105,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
-    public function pageMarginAssertions()
+    public function pageMarginAssertions(): array
     {
         return [
             'Sheet1' => [
diff --git a/tests/PhpSpreadsheetTests/Worksheet/PageMarginsTest.php b/tests/PhpSpreadsheetTests/Worksheet/PageMarginsTest.php
index b9713707..0006a033 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/PageMarginsTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/PageMarginsTest.php
@@ -61,7 +61,7 @@ class PageMarginsTest extends TestCase
         self::assertSame($expectedResult, $actualResult);
     }
 
-    public function providerPointsAndInches()
+    public function providerPointsAndInches(): array
     {
         return [
             [36, 0.5],
@@ -71,7 +71,7 @@ class PageMarginsTest extends TestCase
         ];
     }
 
-    public function providerCentimetersAndInches()
+    public function providerCentimetersAndInches(): array
     {
         return [
             [1.27, 0.5],