private float performCalculations(List<String> parsed, String element, float result, int i) {
        float n1 = Float.valueOf(parsed.get(i - 2));
        float n2 = Float.valueOf(parsed.get(i - 1));

        if (OPERATION_PLUS.equals(element)) {
            result = n1 + n2;
        }
        if (OPERATION_MINUS.equals(element)) {
            result = n1 - n2;
        }
        if (OPERATION_MULTIPLY.equals(element)) {
            result = n1 * n2;
        }
        if (OPERATION_DIVISION.equals(element)) {
            result = n1 / n2;
        }
        changeParsed(parsed, i, result);
        return result;
    }