PHP - Assignment operator

Write a program in PHP that show the use of Assignment Operator, Addition Assignment, Subtraction Assignment, Multiplication Assignment, Divide Assignment 1

<?php
    $a=10; //Assignment Operator
    $a+=5; //Addition Assignment
    echo $a;
    $a-=3 //Subtraction Assignment
    echo $a;
    $a*=2	//Multiplication Assignment
    echo $a;
    $a/=3 //Divide Assignment
    echo $a;
?>