I am trying to build a Bengali calculator. Here is the layout of English calculator :

![Layout of English calculator](https://i.stack.imgur.com/H63XZ.png)

By editing layout I can easily replace English digits with Bengali digits. But when it comes to the calculation i am unable to do it. Like i want it to calculate in Bengali too. e.g it will perform in Bengali like this `(২+২=৪)` instead of `(2+2=4)`. I have tried the replacing method but it didn't work. 

```
Bengali digits(০ ১ ২ ৩ ৪ ৫ ৬ ৭ ৮ ৯)
English digits(1 2 3 4 5 6 7 8 9)

```

Thank you for your time.

```
public class MainActivity extends AppCompatActivity {
    private TextView screen;
    private String str2, result, str, sign;
    private double a, b;
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        screen = (TextView) findViewById(R.id.textview);
        str = "";
    }

    public void onclick(View v) {
        Button button = (Button) v;
        str += button.getText().toString();
        screen.setText(str);
        a = Double.parseDouble(str);
    }
    public void onclicksign(View v) {
        Button button = (Button) v;
        sign = button.getText().toString();
        screen.setText(sign);
        str = "";
    }
    public void calculate(View v) {
        Button button = (Button) v;

        str2 = screen.getText().toString();
        b = Double.parseDouble(str2);
        if (sign.equals("+")) {
            result = a + b + "";
        } else if (sign.equals("-")) {
            result = a - b + "";
        } else if (sign.equals("*")) {
            result = a * b + "";
        } else if (sign.equals("/")) {
            result = a / b + "";
        } else {
            screen.setText("?????? ???");
        }
        {
            screen.setText(result);

        }
    }
}

```