non numerical value warning on cart page

Hey!

I am looking for help regarding the below error message. I am trying to use the measurement price calculator plugin in connection with the woo commerce product table plugin. This error comes on the cart page when entering a quantity in the product table. Thank you much for you help, hugely appreciated!

Warning: A non-numeric value encountered in /homepages/9/d19272688/htdocs/NW/wp-content/plugins/woocommerce-measurement-price-calculator/classes/class-wc-price-calculator-cart.php on line 760

Warning: A non-numeric value encountered in /homepages/9/d19272688/htdocs/NW/wp-content/plugins/woocommerce-measurement-price-calculator/classes/class-wc-price-calculator-cart.php on line 760

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