There are 20 small animals in a row. The elephant ranks 16th from left to right, and the kitten ranks 18th from right to left. How many animals are there between the elephant and the kitten?
一排小动物共有20只，从左往右数大象排第16，从右往左数小猫排第18，大象和小猫之间相隔多少只动物．
<gadget id="calculator">18 - 20 - 2</gadget>
<output>-4</output>

<gadget id="calculator">16 + (-4)</gadget>
<output>12</output>

<result>12</result>