int
double
bool
String
final
const

Types

examples/dart-intro/types.dart

add(x, y) {
  return x+y;
}

main() {
  var name;       // null
  dynamic z = 1; // the same as var, not used

  int age;        // null
  double o7;      // null
  bool isit;      // null
  String email;   // null

  name = 'Foo';
  name = 'Bar';
  

  const address = 'New York';
  //address = "Moscow";
  const double pi = 3 + 0.14;
  final int answer = add(19, 23);
    
  print(z);        // 1
  z++;
  print(z);        // 2
  print(pi);       // 3.14
  print(answer);   // 42
}

Integers are arbitrary precision (but not in JS)
Doubles are 64 bit
Strings are UTF16
Bools are true or false

Variables are either const, final, or ?? (normal?) Both const and final can be assigned only at the time of declaration, but final can be assigned during run-time while const can only get values that are either fixed or can be in-lined. Such as 1+2.