Modular Arithmetic and Partitions

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Are you ready for some fun with modular arithmetic and partitions? Let’s dive in!

To set the stage: what is modular arithmetic? It’s a fancy way of saying that we’re working with numbers that wrap around when they hit certain limits. For example, if I say “it’s 10 o’clock” and you reply “oh, it’s only 2 in the afternoon,” you might be confused because our time zones are different. But what if instead of using a traditional clock, we used one that wraps around every 12 hours? Then when I say “it’s 10 o’clock” and you reply “oh, it’s only 2 in the afternoon,” we both know exactly what time it is!

In math terms, this would be called modular arithmetic with a base of 12. So if we add 4 hours to 10 o’clock (which is really adding 4 * 60 minutes), we get 2 in the afternoon because that’s what happens when you wrap around from 10:00 PM to 2:00 AM!

Now partitions. A partition of a number is just another way of saying how many ways you can add up smaller numbers to make it. For example, the number 5 has three partitions: 5, 4 + 1, and 3 + 2. (Note that we don’t count order here for example, 3 + 2 is considered the same as 2 + 3.)

So what happens when you combine modular arithmetic with partitions? Well, let’s say we want to find all of the ways to add up smaller numbers (less than or equal to a certain number) that result in a particular value (modulo some base). For example, if our base is 10 and we want to find all of the ways to get 5 using only numbers less than or equal to 3, here’s what we do:

– First, let’s write out all of the possible partitions for each number from 0 up to 3 (modulo 10):
0 has one partition: 0.
1 has two partitions: 1 and 0 + 1.
2 has three partitions: 2, 1 + 1, and 0 + 2.
3 has four partitions: 3, 2 + 1, 1 + 2, and 0 + 3.
– Next, let’s look for any partitions that result in a value of 5 (modulo 10). We can do this by subtracting each partition from 5 and checking if the difference is less than or equal to our base:
For example, if we start with the partition 3 + 2, we get a difference of 5 when we subtract it from 5. Since that’s exactly what we want (modulo 10), this gives us one solution!
– Finally, let’s write out all of our solutions:
The partition 3 + 2 has a value of 5 modulo 10.

Modular arithmetic and partitions can be used to solve some pretty interesting problems in math (and even computer science). And the best part?

SICORPS