Difference between understand and understood

Hi,

I have a doubt that somebody tried to explain me a problem then i have to say “Understood” or
“Understand”

Which one is correct ?

I have deliberately written in the above sentence to improve my Writing Skills.This is not the sentence from any context.

Regards
Pavan

I understand (present simple verb)
I understood (past simple verb)

It’s understood. (Adjective)

I just want to know if you are talking to your teacher in the class.

Should I say…

  1. Yes ma’am. I understood!
    or
  2. Yes ma’am. I understand!
    Even if the discussion is still on going…

Yes ma’am, I understood yesterday!

Yes ma’am, I understand right now!

Pleae don’t make duplicate posts, Juliusestella.

Anyhow, my answer would be

I’ve got it. or
I’ve understood.

In my opinion, the present perfect tense should be used in such situations.

It is not necessary, E2.

’ I get it’ or ‘I understand’ work perfectly.

work or works?

“or” makes me confused this time.

In addition please allow me to ask additional question about the difference between “necessary” and “necessarily”.

necessary ~ adjective
necessarily ~ adverb

Please explain when each of them should be used.

Thanks

Does this help?
There are two options.
Both of them work perfectly. Both options work perfectly.

One option works perfectly.
Two options work perfectly.

I am so sorry, ma’am.