<?php class Investment { public $interest; public $amount; public $result; function calculate($interest, $amount) { $this->result = $this->amount * $this->interest + $this->amount; } } $investment = new Investment(); $investment->interest = 0.1; $investment->amount = 250; $investment->calculate($investment->interest, $investment->amount); echo "Finally I calculated that from <br>" . $investment->amount . " \n if we have " . $investment->interest . " we will get " . $investment->result . ". <hr>";