Find the ratio: 49:28; (7/9): (5/6); 0.8: (3/5); 0.5: (2/3).
求比值：49：28；(7/9)：(5/6)；0.8：(3/5)；0.5：(2/3)．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/2) / (2/3)</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>