code: public void start(Activity activity) {
          Intent i = new Intent(activity, CalculatorActivity.class);
          if (!TextUtils.isEmpty(activityTitle)) {
              i.putExtra(CalculatorActivity.TITLE_ACTIVITY, activityTitle);
          }
  
          if (!TextUtils.isEmpty(value)) {
              i.putExtra(CalculatorActivity.VALUE, value);
          }
  
          activity.startActivityForResult(i, CalculatorActivity.REQUEST_RESULT_SUCCESSFUL);
      }
docs: Start the activity using the parent activity
  
  @param activity the current activity