The school buys 9 boxes of chalk, 20 sticks in each box, and uses (1/3). How many branches are left useless?
学校买9盒粉笔，每盒20枝，用去(1/3)．还剩多少枝没有用？
<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">9 * 20 * (2/3)</gadget>
<output>120</output>

<result>120</result>