Я ошибся в одном бланке и попросил у женщины на почте другой.

Ошибся is the past tense, masculine singular form of ошибиться, which means to make a mistake or to be mistaken.

In this sentence, Я ошибся в одном бланке means something like:

• I made a mistake on one form
• literally: I was mistaken in one form

A few useful points:

• я ошибся = I made a mistake (spoken by a man)
• if the speaker were a woman, it would be я ошиблась
• the verb is reflexive because of -ся

So ошибиться is a very common Russian way to say that you got something wrong.

Because the verb ошибиться often uses the pattern:

• ошибиться в чём-то = to make a mistake in something

So:

• в бланке = in the form
• в одном бланке = in one form

After в in this meaning, Russian uses the prepositional case, so:

• бланк → в бланке
• один → в одном

That is why both words change form.

Бланк means a form, especially an official paper you fill out.

Depending on context, it can be translated as:

• form
• blank form
• sometimes just document form

So here в одном бланке means on one of the forms / in one form that I was filling out.

Because один has to match the case of бланке.

The noun бланк is in the prepositional case after в, so the adjective/number word that goes with it must also be in the prepositional case:

• nominative: один бланк
• prepositional: в одном бланке

This is normal Russian agreement: words that describe a noun usually change along with the noun.

Попросил is the perfective form of the verb, from попросить.

Here it means a completed single action:

• попросил = asked
• просил = was asking / asked repeatedly / asked in general

In this sentence, the speaker made one specific request, so попросил is the natural choice.

Compare:

• Я попросил другой бланк. = I asked for another form.
• Я просил другой бланк. = I was asking for another form / I asked for another form (with focus on process or repetition).

Because Russian often says:

• попросить у кого-то что-то = to ask someone for something

So the person you are asking from goes after у:

• у женщины = from the woman
• попросил у женщины другой бланк = asked the woman for another form

This is different from English, where we usually say ask someone for something.

In Russian, both patterns exist, but попросить у кого-то что-то is very common.

Женщины is in the genitive case because it comes after the preposition у.

The preposition у normally requires the genitive:

• у женщины = from the woman / at the woman’s place depending on context

Here it means from the woman, as part of the structure:

• попросить у женщины другой бланк
• ask the woman for another form

No. На почте is the normal Russian way to say at the post office.

The word почта can mean:

• mail
• post
• post office

In this phrase, на почте means at the post office.

Russian often uses на with places or institutions where English uses at:

• на почте = at the post office
• на работе = at work
• на вокзале = at the train station uses на? Actually на вокзале is fixed too.

So here у женщины на почте means from the woman at the post office.

Russian often leaves out a noun when it is obvious from context.

Here другой means:

• another one
• more literally: another [form]

The noun бланк is understood, so it does not need to be repeated.

This works just like English:

• I need another form.
• I made a mistake, so I asked for another.

In Russian:

• попросил другой бланк = full version
• попросил другой = shorter version, with бланк understood

Because it refers to the implied noun бланк, which is:

• masculine
• singular
• here functioning as the direct object

So другой is in the masculine singular form to match the missing noun бланк.

Compare:

• другой бланк = another form
• другая анкета = another questionnaire
• другое письмо = another letter
• другие документы = other documents

Even when the noun is omitted, the adjective still shows its gender and number.

In Russian past tense, verbs agree with the subject in gender and number.

So if the speaker is a man:

• я ошибся
• я попросил

If the speaker is a woman:

• я ошиблась
• я попросила

This is something English does not do, so it often stands out to learners.

Literally, женщина means woman.

So у женщины на почте literally means from the woman at the post office.

In natural English, depending on context, you might translate it more smoothly as:

• from the woman at the post office
• from the postal clerk
• from the woman working at the post office

Russian sometimes uses a simple everyday noun like женщина, where English might prefer a job title.

И simply means and.

It connects two past actions:

1. Я ошибся в одном бланке = I made a mistake on one form
2. и попросил у женщины на почте другой = and asked the woman at the post office for another one

So the whole sentence describes a sequence:

• first, the speaker made a mistake
• then, the speaker asked for a new form

Yes. Russian word order is flexible, though different orders can sound more or less natural depending on what you want to emphasize.

This version:

• Я ошибся в одном бланке и попросил у женщины на почте другой.

is natural and clear.

You could also hear things like:

• Я ошибся в одном бланке и попросил другой у женщины на почте.
• На почте я ошибся в одном бланке и попросил у женщины другой.

These are all possible, but the original sentence is a good neutral order.

Russian word order often helps show focus rather than basic grammar, since the case endings already show grammatical roles.

It is understandable and grammatical with ошибиться в чём-то, but learners may notice that Russian can express this idea in a few ways depending on context.

For example, native speakers might also say things like:

• ошибся в бланке
• допустил ошибку в бланке
• неправильно заполнил один бланк

These have slightly different shades of meaning:

• ошибся в бланке = made a mistake in the form
• допустил ошибку в бланке = made an error in the form
• неправильно заполнил = filled it out incorrectly

So the sentence is fine, but there are other natural ways to say similar things.

Yes. A very useful pattern here is:

• Я ошибся в X и попросил у Y другой.

Examples:

• Я ошибся в анкете и попросил у сотрудника другую.
  I made a mistake on the application form and asked the employee for another one.

• Я ошибся в документе и попросил у секретаря другой экземпляр.
  I made a mistake in the document and asked the secretary for another copy.

The key pieces are:

• ошибиться в чём-то = make a mistake in something
• попросить у кого-то что-то = ask someone for something
• другой / другая / другое = another one, matching the missing noun