diff --git a/src/Math/Reader/MathML.php b/src/Math/Reader/MathML.php
index 8416988..275fe98 100644
--- a/src/Math/Reader/MathML.php
+++ b/src/Math/Reader/MathML.php
@@ -61,7 +61,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
             case 'mfrac':
                 $element = new Element\Fraction();
                 $nodeList = $this->xpath->query('*', $nodeElement);
-                if ($nodeList->count() == 2) {
+                if ($nodeList->length == 2) {
                     $element
                         ->setNumerator($this->getElement($nodeList->item(0)))
                         ->setDenominator($this->getElement($nodeList->item(1)));
@@ -75,7 +75,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
                 if (empty($nodeValue)) {
                     $nodeList = $this->xpath->query('*', $nodeElement);
                     if (
-                        $nodeList->count() == 1 
+                        $nodeList->length == 1 
                         && $nodeList->item(0)->nodeName == 'mchar'
                         && $nodeList->item(0)->hasAttribute('name')
                     ) {
@@ -88,7 +88,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
             case 'msup':
                 $element = new Element\Superscript();
                 $nodeList = $this->xpath->query('*', $nodeElement);
-                if ($nodeList->count() == 2) {
+                if ($nodeList->length == 2) {
                     $element
                         ->setBase($this->getElement($nodeList->item(0)))
                         ->setSuperscript($this->getElement($nodeList->item(1)));
diff --git a/src/Math/Reader/OfficeMathML.php b/src/Math/Reader/OfficeMathML.php
index 63c2047..3a701eb 100644
--- a/src/Math/Reader/OfficeMathML.php
+++ b/src/Math/Reader/OfficeMathML.php
@@ -67,7 +67,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
                 $element = new Element\Fraction();
                 // Numerator
                 $nodeNumerator = $this->xpath->query('m:num/m:r/m:t', $nodeElement);
-                if ($nodeNumerator->count() == 1) {
+                if ($nodeNumerator->length == 1) {
                     $value = $nodeNumerator->item(0)->nodeValue;
                     if (is_numeric($value)) {
                         $element->setNumerator(new Element\Numeric($value));
@@ -77,7 +77,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
                 }
                 // Denominator
                 $nodeDenominator= $this->xpath->query('m:den/m:r/m:t', $nodeElement);
-                if ($nodeDenominator->count() == 1) {
+                if ($nodeDenominator->length == 1) {
                     $value = $nodeDenominator->item(0)->nodeValue;
                     if (is_numeric($value)) {
                         $element->setDenominator(new Element\Numeric($value));
@@ -88,7 +88,7 @@ protected function getElement(DOMElement $nodeElement): Element\AbstractElement
                 return $element;
             case 'm:r':
                 $nodeText = $this->xpath->query('m:t', $nodeElement);
-                if ($nodeText->count() == 1) {
+                if ($nodeText->length == 1) {
                     $value = trim($nodeText->item(0)->nodeValue);
                     if (in_array($value, $this->operators)) {
                         return new Element\Operator($value);