PHP Conditional Logic And Operator

<?php

$n = 12;
if ($n % 2 == 0){
    echo "$n is a even number";
}else{
    echo "$n is a odd number";
}

echo "<br/>";

if ($n > 10) {
    echo "$n is greater then 10";
}


echo "<br/>";


$m = 12;
$s = 13;

if ($m != $s) {
    echo "M is qual to N";
}else{
    echo "M is not equal to N";
}



echo "<br/>";


$age = 13;

if ($age >= 13 && $age <=19) {
    echo "This is a teenager";
}else{
    echo "this person not a teenager";
}


echo "<br/>";


$food = "salmon";

if ("tuna" == $food || "salmon" == $food) {
    echo "{$food} has vitamin D";
}elseif ("apple"==$food) {
    echo "Apple dose not contain vitamin D";
}else{
    echo "we dont know if {$food} contain vitamin D";
}


// Operator

/*==
!=
>
<
=>
>=
&&
||*/