        <option value="-">-</option>
                    <option value="/">/</option>
                    <option value="*">*</option>
                    <option value="**">**</option>
                </select>
            </label>
            <label>
                <input id="secondValue" class="value-box">
            </label>
            <button id="calculate" type="button" class="button-box">=</button>
            <span id="result" class="res-view"></span>
        </div>
        <script src="./script.