A silk ribbon is 100 cm long. Xiaofang uses (2/5) of this ribbon to make a Chinese knot. How many centimeters does she use?
一根绸带长100厘米，小芳用这根绸带的(2/5)做中国结，用去多少厘米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">100 * (2/5)</gadget>
<output>40</output>

<result>40</result>