final Button point = new ButtonDigit(controller, ".");
g.setWidget(3, 2, point);
// put the operators in the grid
final Button divide = new ButtonOperator(controller,
new OperatorDivide());
g.setWidget(0, 3, divide);
final Button multiply = new ButtonOperator(controller,
new OperatorMultiply());
g.setWidget(1, 3, multiply);