$number = 15; printf("Decimal: %d", $number); //Decimal: 15 printf("Binary: %b", $number); //Binary: 1111 printf("Double: %f", $number); //Double: 15.000000 printf("Octal: %o", $number); //Octal: 17 printf("String: %s", $number); //String: 15 printf("Hex (lower): %x", $number); //Hex (lower): f printf("Hex (upper): %X", $number); //Hex (upper): F