: It is still frequently referenced today whenever someone makes a glaringly obvious math error.
: The audio has been mixed into songs, movie trailers, and other viral trends on platforms like TikTok and Instagram.
The video thrived because of its perfect comedic timing and the boy's unwavering confidence in such a clearly incorrect answer. While the actual answer is 19, the boy's "21" became a shorthand for being . 9 / 10 123movies133...
Even after the Vine app shut down in 2017, the meme lived on through:
The dialogue that launched a thousand remixes went like this: "You stupid." Kid: "No I'm not." Brother: "What's 9 plus 10?" Kid: (Without a second's hesitation) " 21 ." Brother: "You stupid." Why It Became a Legend : It is still frequently referenced today whenever
: People created absurd logical loops to "prove" the kid was actually a genius and that 9 + 10 really does equal 21.
The story began in 2013 with a short, six-second video that captured a simple yet hilariously confident mistake. In the clip, an older brother is recording his younger brother, who would eventually be known across the internet as the "21 Kid". While the actual answer is 19, the boy's
original sound - soundeffectpack ... Stupid? No, not. What's 9 + 10? 21, you stupid. TikTok·althea420