const a = 10 + '20';                 // the sum of integer and string values
const b = '20' + '20';                   // the sum of two string values
console.log(a, b);                       // returns "1020" , "2020" 
console.log(typeof(a, b));          // both are strings

$a = 10 + '20';                          // The sum of an integer and a string
$b = '1020' + '20';                        // The sum two strings
echo $a, "\n ", $b, "<br>";         // returns 30, 1040 
echo var_dump($a, $b);            // both are integers (int+str) (str+str)

$integer = 10;
$stringIncrement = '20';
$result = $integer + $stringIncrement;
$result = (string) $result;
var_dump($result);