If x and y are in direct proportion, when x=16, у=0.8; if x=10, what is у.
如果x和y成正比例，当x=16时，у=0.8；如果x=10时，у是多少．
<gadget id="calculator">0.8 * 10</gadget>
<output>8</output>

<gadget id="calculator">8 / 16</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>