It’s not undoing the division, it never happens in the first place. Remainders aren’t ever fractions, that’s the whole point, they’re left over because they can’t be divided evenly. 5 % 2, you can take 2 away twice and you’ll have 1 left over which can’t have 2 taken away.
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moosetwin@lemmy.dbzer0.com 3 weeks ago[deleted]
chaos@beehaw.org 3 weeks ago
Rivalarrival@lemmy.today 3 weeks ago
Modulo is much easier to understand with clocks.
Suppose It is currently midnight. What time will it be in 3 hours? 3 mod 24 = 3. It will be 03:00
What time will it be in 27 hours? 27 mod 24 = 3. It will be 03:00 we go through a whole day (24 hours) to get back to midnight, then another 3 hours.
What time will it be 48 hours from now? 48 mod 24 = 0. 48 hours from midnight will be midnight.
What time will it be 6 hours from now? 6 mod 24 = 6.
Conceptually, X mod Y means that instead of 24 hours per day, we are splitting the day into Y “hours”, labeled 0 to Y-1. We start at 0, and pass through X “hours”. X mod Y is the “hour” we finish up in at the end. 5 mod 2 means we have a 2-hour day, with hours 0 and 1. We pass through 5 of those hours. When we finish, are we at hour 0 or hour 1?
jeff@programming.dev 3 weeks ago
You are misunderstanding what the remainder is.
5 % 2 == 1, because 5 == 2 x 2 + 1
10 % 7 == 3, because 10 == 1 x 7 + 3
Your “edit 2” is mostly correct. I don’t think of it “undoing” the division. But if that makes sense to you then I guess it’s fine