The Olympic Games are held every 4 years, and 2008 is the 29th Beijing Olympic Games, so how many years is the 20th Olympic Games?
奥运会每4年举行一次，2008年是北京第二十九届，那么第二十届奥运会是在多少年．
<gadget id="calculator">29 - 20</gadget>
<output>9</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">2_008 - 36</gadget>
<output>1_972</output>

<result>1_972</result>