Fill in the blanks according to the law: (1/2), (7/3), (13/5), (19/8), how much, (31/21).
按规律填空：(1/2)、(7/3)、(13/5)、(19/8)、多少、(31/21)．
<gadget id="calculator">19 + 6</gadget>
<output>25</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">25 / 13</gadget>
<output>25/13 = around 1.923077</output>

<result>25/13 = around 1.923077</result>