In the following 9 fractional formulas: ①(3/5)+(5/20), ②(3/6)+(6/20), ③(3/7)+(7/20), ④(3 /8)+(8/20), ⑤(3/9)+(9/20), ⑥(3/10)+(10/20), ⑦(3/11)+(11/20), ⑧ (3/12)+(12/20), ⑨(3/13)+(13/20), which formula has the smallest result? What is this result equal to?
在下面9个分数算式中：①(3/5)+(5/20)，②(3/6)+(6/20)，③(3/7)+(7/20)，④(3/8)+(8/20)，⑤(3/9)+(9/20)，⑥(3/10)+(10/20)，⑦(3/11)+(11/20)，⑧(3/12)+(12/20)，⑨(3/13)+(13/20)，第几个算式的结果最小？这个结果等于多少？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">8 / 20</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/8) + (2/5)</gadget>
<output>31/40 = around 0.775</output>

<result>31/40 = around 0.775</result>