declare(strict_types=1); // Строгое требование <html><body>function sum(int $x, int $y) { $z = $x + $y; return $z;}echo "5 + 10 = " . sum(5,10) . "<br>";echo "7 + 13 = " . sum(7,13) . "<br>";echo "2 + 4 = " . sum(2,4);</body></html>