Fatal error: Uncaught DivisionByZeroError: Modulo by zero in C:\xampp\htdocs\imperial\theophylline-and\index.php:3 Stack trace: #0 C:\xampp\htdocs\imperial\theophylline-and\index.php(3): _32uwt9->_4dp40() #1 {main} thrown in C:\xampp\htdocs\imperial\theophylline-and\index.php on line 3