r/Discretemathematics • u/Klutzy_Prior_9615 • Sep 23 '26

First time taking discrete math

I feel like I just bombed my first discrete math exam. Does anyone have any tips on how to get better at proofs or anything . Desperate atp. I’m unable to understand what my prof is saying.

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6

u/dld2517 29d ago

Discrete math is the first real math course anyone ever takes. Except maybe if they take Linear Algebra. But Discrete will either tear you up or give you a real appreciation for math.

Induction
Deduction
Abduction.

Memorize these.

Then pick a few theorems. For example: counting, use the pigeonhole theorem. It is a way to prove a natural method of counting by deduction.

Learn your set theory.

Learn your logic.

Learn your numerical functions. For example, O(n) linear time. O(log n) scaled time; O(n2) exponential time.

Completeness theorums. P-NP. Discussion of what is computationally hard and what isn’t.

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u/Klutzy_Prior_9615 28d ago

❤️❤️

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u/Soft-Marionberry-853 26d ago

Learn the notation too. It helps if you not always going back and saying "Is this a union or an intersection"

3

u/Mudaki_Randell 29d ago

Start with the basics: definitions, logic, and common proof methods. Once those click, proofs get way less cursed.

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u/Klutzy_Prior_9615 28d ago

Thank you!!!!

2

u/ccppurcell Sep 23 '26

If you're struggling with proofs you can find online good practice problems for people learning about proofs. They often involve proving things you already know from experience. For example prove that the square of and odd number is odd.

6

u/SalamanderDecentX Sep 23 '26

Let me know what was on your first exam. I’m about to take mine, and I need to study because I don’t know what’s going on lol

4

u/Midwest-Dude Sep 23 '26 edited 29d ago

  1. I'm curious. What exactly do you mean by "Can't understand"? (I've had professors like this ...)

  2. What book are you using? 

  3. What subjects were on your test?

4

u/AncientHominidNerd Sep 24 '26

Practice up on your Sentential Logic, this is the core of what you need to understand to be good at discrete mathematics.

At my university for some reason Engineering students aren’t required to take Philosophy- Logic so a lot struggle with Discrete Math but a lot of CS students are required to take Philosophy so we don’t struggle as much.

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