In this study, we investigate key strands of mathematical narratives across Korean social media. Mathematical content can be discussed within social communities because mathematics has a social nature. Citizens can share their thoughts on mathematical content through social media, drawing from their basic mathematical skills or previous experiences. Social media serves as a platform for this discussion but also as a public forum for broader communication about mathematics. YouTube Shorts, a feature introduced in 2021, offers an accessible platform for citizens to engage with a diverse range of topics, including mathematical content, all within one minute. Following the analysis of 95 Korean YouTube Shorts videos, four key strands were identified: Mathematics introductions, arithmetic methods, creative mathematics challenges, and controversial mathematical topics. The comments on YouTube Shorts served as a platform for discussing mathematics. The findings of this study illuminate the types of mathematical narratives and aspects of citizens’ communication about mathematics in YouTube Shorts. This study can also provide implications for developing citizens’ numeracy.