There are 53 wild ducks on the artificial wild duck island this year, and last year there were 18 less than this year. How many ducks were there last year?
人工野鸭岛今年有53只野鸭，去年比今年少18只，去年有多少只？
<gadget id="calculator">53 - 18</gadget>
<output>35</output>

<result>35</result>