Add parentheses to 4*7+40/8+9, what is the calculated minimum result
在算是4*7+40/8+9中添加小括号，计算出的最小结果是多少
<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<gadget id="calculator">28 + 40</gadget>
<output>68</output>

<gadget id="calculator">8 + 9</gadget>
<output>17</output>

<gadget id="calculator">68 / 17</gadget>
<output>4</output>

<result>4</result>