subtractButton.setOnClickListener(l -> {
        if (value1.getText().toString().isEmpty() || value2.getText().toString().isEmpty()) {
            Toast.makeText(this, "Введите сначала значения", Toast.LENGTH_LONG).show();
            resultView.setText("ERROR");
            return;
        }
        Float v1 = Float.parseFloat(value1.getEditableText().toString());
        Float v2 = Float.parseFloat(value2.getEditableText().toString());
        Float result = v1 - v2;
        resultView.setText(result.toString());
    });