At 6:40, what is the acute angle formed by the hour and minute hands?
6点40分时，时针和分针所构成的锐角是多少度．
<gadget id="calculator">40 / 60</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 - (2/3)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">30 * (4/3)</gadget>
<output>40</output>

<result>40</result>