Does 0.4999... Round Up or Down? The Truth About Infinite Decimals 🔢
Discover how to round 0.4999... and why it's considered closer to 0.5. Learn the math behind infinite decimals and rounding rules in this clear explanation!

Wrath of Math
287.9K views • Jul 12, 2025

About this video
Pretty much everyone knows that 0.999... = 1, and certainly, even if you argue about that - you might concede that if we were to round 0.999... it would round to 1. But what about 0.4999...? Does this round to 0 or to 1? Today we answer this question by exploring rounding conventions and discussing why 0.4999... is 0.5 in the first place. This question comes from r/askmath. #maths #reddit
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SOURCES
https://www.reddit.com/r/askmath/comments/1lukdbz/when_rounding_to_the_nearest_whole_number_does/
https://en.wikipedia.org/wiki/Rounding
0:00 Intro
1:00 Floor and Ceiling
2:12 The Nearest Whole
5:01 Why Round Up?
9:04 Banker's Rounding
11:51 Mathshion
12:28 Why 0.4999...=0.5
16:58 Final Question
18:04 "Mathematically"
18:52 Conclusion
Check out the coolest math clothes in the world: https://mathshion.com/
Join Wrath of Math to get exclusive videos, lecture notes, and more:
https://www.youtube.com/channel/UCyEKvaxi8mt9FMc62MHcliw/join
More Math Chats: https://www.youtube.com/playlist?list=PLztBpqftvzxXQDmPmSOwXSU9vOHgty1RO
Outro music: https://youtube.com/shorts/tfifiSdTZRg
Follow Wrath of Math on...
● Instagram: https://www.instagram.com/wrathofmathedu
● TikTok: https://www.tiktok.com/@wrathofmathedu
● X: https://x.com/wrathofmathedu
SOURCES
https://www.reddit.com/r/askmath/comments/1lukdbz/when_rounding_to_the_nearest_whole_number_does/
https://en.wikipedia.org/wiki/Rounding
0:00 Intro
1:00 Floor and Ceiling
2:12 The Nearest Whole
5:01 Why Round Up?
9:04 Banker's Rounding
11:51 Mathshion
12:28 Why 0.4999...=0.5
16:58 Final Question
18:04 "Mathematically"
18:52 Conclusion
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Video Information
Views
287.9K
Likes
8.3K
Duration
19:53
Published
Jul 12, 2025
User Reviews
4.7
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