What is the product of the largest and smallest number among (49/61), (61/73), (4/5), and (31/40)?
(49/61)、(61/73)、(4/5)和(31/40)中最大数与最小数之积是多少？
<gadget id="calculator">61 / 73</gadget>
<output>61/73 = around 0.835616</output>

<gadget id="calculator">31 / 40</gadget>
<output>31/40 = around 0.775</output>

<gadget id="calculator">(61/73) * (31/40)</gadget>
<output>1_891/2_920 = around 0.647603</output>

<result>1_891/2_920 = around 0.647603</result>