A kind of worm doubles in size every day, and grows to 10 mm in 10 days. How many days does it take to grow to 1.25 mm?
一种虫，每天长1倍，10天长到10毫米，长到1.25毫米要多少天．
<gadget id="calculator">1.25 * 8</gadget>
<output>10</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<result>7</result>