The supermarket brings in 20 kg of apples, the weight of oranges is 90% of the weight of apples, and the weight of grapes is 1/3 less than that of oranges. What is the weight of grapes in kilograms?
超市运进20千克苹果，桔子的重量是苹果的90%，葡萄的重量比桔子少(1/3)，葡萄重多少千克．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">20 * (9/10) * (2/3)</gadget>
<output>12</output>

<result>12</result>