{ private $number; public function setInitialNumber($number) { $this->number = $number; } public function add($num) { $this->number += $num; } public function subtract($num) { $this->number -= $num; } public function multiply($num) { $this->number *= $num; } public function getFinalNumber() { return $this->number; } } $m = new maths(); $m->setInitialNumber(5); $m->add(4); $m->subtract(1); $m->multiply(2); $m->add(2); echo $m->getFinalNumber();