A manuscript is 2,000 words, 40% of which has been typed, how many words are left untyped.
一份稿件2000字，已经打了40%，还剩多少字没有打．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">2_000 * (3/5)</gadget>
<output>1_200</output>

<result>1_200</result>