Tipneme si odpověď a odevzdáme odpovědní arch.

In Czech, these are perfective verbs, and perfective verbs normally use their “present-tense” forms to express a future completed action.

So:

• tipneme si = we will make a guess
• odevzdáme = we will hand in / submit

This is very common in Czech. A literal form that looks present to an English speaker often has future meaning when the verb is perfective.

For comparison:

• tipujeme = we are guessing / we guess repeatedly or generally

• tipneme si = we’ll take a guess

• odevzdáváme = we are handing in / we hand in
• odevzdáme = we will hand in

Usually, no direct English word is needed.

Si is a short reflexive/dative particle that often appears in idiomatic verbs. In tipnout si, it helps form the natural Czech expression meaning to take a guess or to make a guess.

So:

• tipnout odpověď is less natural here
• tipnout si odpověď is the normal idiomatic phrasing

You can think of it as something like have oneself a guess, but that is only a rough aid. In normal English translation, you usually just ignore si and say guess.

Because Czech usually does not need subject pronouns when the verb ending already shows who is doing the action.

Both verbs clearly show 1st person plural:

• tipneme = we will guess
• odevzdáme = we will submit

So adding my would usually be unnecessary unless you want emphasis:

• My tipneme si odpověď... = We will guess the answer...
  This sounds more emphatic, like contrasting we with someone else.

Here odpověď is the direct object of tipneme si, so it is in the accusative case.

The tricky part is that for this noun, the nominative and accusative singular look the same:

• nominative: odpověď = answer
• accusative: odpověď = answer

So even though the form does not change, the function does: in this sentence it means the answer as the thing being guessed.

It is more specific than simple give.

Odevzdat means to hand in, to submit, or to turn in something, especially in a school or test context.

So odevzdáme odpovědní arch means:

• we will hand in the answer sheet
• we will submit the answer sheet

This is the natural verb for giving a paper, test, form, or assignment to the teacher/examiner.

In Czech, arch means a sheet of paper, often a larger sheet or a form-like sheet.

So odpovědní arch means answer sheet.

This is a good example of a false friend: Czech arch is not related in meaning to English arch as in a curved structure.

Because odpovědní here is a different adjective, meaning something like answer- / response-related, not responsible.

So:

• odpovědný = responsible
• odpovědní arch = answer sheet

The adjective odpovědní declines like adjectives such as jarní. It agrees with arch in gender, number, and case.

In this sentence:

• odpovědní arch is masculine inanimate singular
• as the object of odevzdáme, it is in the accusative
• for masculine inanimate nouns, accusative singular looks like nominative singular

So the form stays odpovědní arch.

Yes. Czech word order is flexible, although the original order is very natural.

Tipneme si odpověď a odevzdáme odpovědní arch. presents the actions in a straightforward sequence: first guess, then hand in.

You could change the order for emphasis, for example:

• Odpověď si tipneme a odevzdáme odpovědní arch.
• Odevzdáme odpovědní arch a tipneme si odpověď.

But those versions shift the focus or sound less neutral depending on context. The original sentence is the best neutral version for most situations.

It is fairly neutral, but tipnout si is a bit more conversational than a very formal exam-style verb.

It sounds natural in everyday speech or in instructions said casually among students. In a more formal context, Czech might use something like a verb meaning select or choose an answer, depending on the situation.

So the sentence is perfectly normal, but tipnout si has the flavor of take a guess rather than a highly formal instruction.