diff --git a/src/PhpSpreadsheet/Cell/Cell.php b/src/PhpSpreadsheet/Cell/Cell.php
index d20b8a56..cdef9018 100644
--- a/src/PhpSpreadsheet/Cell/Cell.php
+++ b/src/PhpSpreadsheet/Cell/Cell.php
@@ -217,6 +217,9 @@ class Cell
 
                 break;
             case DataType::TYPE_NUMERIC:
+                if (is_string($pValue) && !is_numeric($pValue)) {
+                    throw new Exception('Invalid numeric value for datatype Numeric');
+                }
                 $this->value = 0 + $pValue;
 
                 break;
diff --git a/src/PhpSpreadsheet/Shared/JAMA/QRDecomposition.php b/src/PhpSpreadsheet/Shared/JAMA/QRDecomposition.php
index e666d74b..3bb8a10e 100644
--- a/src/PhpSpreadsheet/Shared/JAMA/QRDecomposition.php
+++ b/src/PhpSpreadsheet/Shared/JAMA/QRDecomposition.php
@@ -60,7 +60,7 @@ class QRDecomposition
     {
         if ($A instanceof Matrix) {
             // Initialize.
-            $this->QR = $A->getArrayCopy();
+            $this->QR = $A->getArray();
             $this->m = $A->getRowDimension();
             $this->n = $A->getColumnDimension();
             // Main loop.
diff --git a/tests/PhpSpreadsheetTests/Cell/CellTest.php b/tests/PhpSpreadsheetTests/Cell/CellTest.php
index 884ed239..d8c38585 100644
--- a/tests/PhpSpreadsheetTests/Cell/CellTest.php
+++ b/tests/PhpSpreadsheetTests/Cell/CellTest.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheetTests\Cell;
 
+use PhpOffice\PhpSpreadsheet\Exception;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PHPUnit\Framework\TestCase;
 
@@ -27,4 +28,26 @@ class CellTest extends TestCase
     {
         return require 'data/Cell/SetValueExplicit.php';
     }
+
+    /**
+     * @dataProvider providerSetValueExplicitException
+     *
+     * @param mixed $expected
+     * @param mixed $value
+     * @param string $dataType
+     */
+    public function testSetValueExplicitException($value, string $dataType)
+    {
+        $this->expectException(Exception::class);
+
+        $spreadsheet = new Spreadsheet();
+        $cell = $spreadsheet->getActiveSheet()->getCell('A1');
+        $cell->setValueExplicit($value, $dataType);
+    }
+
+    public function providerSetValueExplicitException()
+    {
+        return require 'data/Cell/SetValueExplicitException.php';
+    }
+
 }
diff --git a/tests/data/Cell/SetValueExplicit.php b/tests/data/Cell/SetValueExplicit.php
index 3ac039fe..50b81019 100644
--- a/tests/data/Cell/SetValueExplicit.php
+++ b/tests/data/Cell/SetValueExplicit.php
@@ -8,19 +8,44 @@ return [
         '01234567890123456789',
         DataType::TYPE_NUMERIC,
     ],
+    [
+        1234567890123456789,
+        1234567890123456789,
+        DataType::TYPE_NUMERIC,
+    ],
     [
         123.456,
         '123.456',
         DataType::TYPE_NUMERIC,
     ],
     [
-        1234567890123456789,
-        1234567890123456789,
+        123.456,
+        123.456,
         DataType::TYPE_NUMERIC,
     ],
     [
-        123.456,
-        123.456,
+        0,
+        null,
         DataType::TYPE_NUMERIC,
     ],
+    [
+        0,
+        false,
+        DataType::TYPE_NUMERIC,
+    ],
+    [
+        1,
+        true,
+        DataType::TYPE_NUMERIC,
+    ],
+    [
+        '#DIV/0!',
+        '#DIV/0!',
+        DataType::TYPE_ERROR,
+    ],
+    [
+        '#NULL!',
+        'NOT A VALID ERROR TYPE VALUE',
+        DataType::TYPE_ERROR,
+    ],
 ];
diff --git a/tests/data/Cell/SetValueExplicitException.php b/tests/data/Cell/SetValueExplicitException.php
new file mode 100644
index 00000000..a05704f0
--- /dev/null
+++ b/tests/data/Cell/SetValueExplicitException.php
@@ -0,0 +1,10 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Cell\DataType;
+
+return [
+    [
+        'XYZ',
+        DataType::TYPE_NUMERIC,
+    ],
+];