diff --git a/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php b/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
index 7b1ffa9eba..37070e2434 100644
--- a/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
+++ b/src/PhpSpreadsheet/Calculation/MathTrig/Sum.php
@@ -18,7 +18,7 @@ class Sum
      *
      * @param mixed ...$args Data values
      *
-     * @return float|string
+     * @return float|int|string
      */
     public static function sumIgnoringStrings(...$args)
     {
@@ -47,7 +47,7 @@ public static function sumIgnoringStrings(...$args)
      *
      * @param mixed ...$args Data values
      *
-     * @return float|string
+     * @return float|int|string
      */
     public static function sumErroringStrings(...$args)
     {
@@ -56,10 +56,7 @@ public static function sumErroringStrings(...$args)
         $aArgs = Functions::flattenArrayIndexed($args);
         foreach ($aArgs as $k => $arg) {
             // Is it a numeric value?
-            if (is_numeric($arg) || empty($arg)) {
-                if (is_string($arg)) {
-                    $arg = (int) $arg;
-                }
+            if (is_numeric($arg)) {
                 $returnValue += $arg;
             } elseif (is_bool($arg)) {
                 $returnValue += (int) $arg;
diff --git a/tests/data/Calculation/MathTrig/SUM.php b/tests/data/Calculation/MathTrig/SUM.php
index 0c54613e2a..ad2c78e0ce 100644
--- a/tests/data/Calculation/MathTrig/SUM.php
+++ b/tests/data/Calculation/MathTrig/SUM.php
@@ -5,7 +5,9 @@
     [52, 5, 15, 30, 2],
     [53.1, 5.7, 15, 30, 2.4],
     [52.1, 5.7, '14', 30, 2.4],
+    [52.2, 5.7, '14.1', 30, 2.4],
     [38.1, 5.7, 'X', 30, 2.4], // error if entered in formula, but not in cell
+    [38.1, 5.7, '', 30, 2.4], // error if entered in formula, but not in cell
     [38.1, 5.7, null, 30, 2.4],
     [38.1, 5.7, false, 30, 2.4],
     [39.1, 5.7, true, 30, 2.4],
diff --git a/tests/data/Calculation/MathTrig/SUMLITERALS.php b/tests/data/Calculation/MathTrig/SUMLITERALS.php
index fd184ebd50..0ea5938617 100644
--- a/tests/data/Calculation/MathTrig/SUMLITERALS.php
+++ b/tests/data/Calculation/MathTrig/SUMLITERALS.php
@@ -5,7 +5,9 @@
     [52, '5, 15, 30, 2'],
     [53.1, '5.7, 15, 30, 2.4'],
     [52.1, '5.7, "14", 30, 2.4'],
+    [52.2, '5.7, "14.1", 30, 2.4'],
     ['#VALUE!', '5.7, "X", 30, 2.4'], // error if entered in formula, but not in cell
+    ['#VALUE!', '5.7, "", 30, 2.4'], // error if entered in formula, but not in cell
     [38.1, '5.7, , 30, 2.4'],
     [38.1, '5.7, false, 30, 2.4'],
     [39.1, '5.7, true, 30, 2.4'],