Number-button.dart

import 'package:flutter/material.dart';

class NumberButton extends StatelessWidget {
 NumberButton({this.text,this.onPressed});

 final String text;
 final Function onPressed;

 @override
 Widget build(BuildContext context) {
   return Padding(
       padding: const EdgeInsets.all(5.0),
       child: RawMaterialButton(
           shape: const CircleBorder(),
           constraints: BoxConstraints.tight(Size(60.0, 60.0)),
           onPressed:onPressed,
         child: Text(
           text,
           style: TextStyle(color: Colors.white, fontSize: 20.0),
         ),
         fillColor: Color.fromRGBO(56, 54, 56, 1.0),
           ));
 }
}