Мы разделили пирог поровну и начали пить чай.

Yes, it can.

Russian often leaves out subject pronouns when the subject is clear from context. So Разделили пирог поровну и начали пить чай can be a perfectly natural sentence.

One small detail: in the past tense, Russian verbs show number and, in the singular, gender, but they do not show person clearly the way present-tense verbs do. So разделили and начали tell you that more than one person did the action, but not automatically that it was we. Because of that, мы is useful when the speaker wants to make the subject explicit.

Разделили is:

• past tense
• plural
• perfective
• from разделить

The perfective aspect is used because the dividing is presented as a completed action. The idea is:

• first, we finished dividing the pie,
• then, we began drinking tea.

If you used an imperfective verb such as делили or разделяли, the focus would be more on the process of dividing, not on its completion.

Because пирог is the direct object of разделили, so it is in the accusative case.

For inanimate masculine singular nouns, the accusative form is usually the same as the nominative form. So:

• nominative: пирог
• accusative: пирог

That is why the form does not change here.

Поровну is an adverb meaning equally, into equal parts, or so that everyone gets the same amount.

So разделили пирог поровну means something like:

• divided the pie equally
• split the pie evenly
• shared the pie in equal portions

It is a very common word in situations involving sharing or dividing something fairly.

Yes. Russian word order is flexible, so you can move поровну for slightly different emphasis.

For example:

• Мы разделили пирог поровну и начали пить чай.
• Мы поровну разделили пирог и начали пить чай.

Both are natural. The original version is very neutral. Putting поровну earlier can emphasize the idea of equal sharing a bit more.

Because Russian commonly uses начать / начинать + infinitive to mean to begin doing something.

So:

• начали = began
• пить = to drink

Together, начали пить чай means began to drink tea or started drinking tea.

This is a normal and very common structure in Russian.

Because after начать, Russian normally uses an imperfective infinitive.

Here the focus is on starting the process of drinking tea, so пить is the natural choice.

• пить = to drink, process/activity
• выпить = to drink up, finish drinking, consume a serving

You generally do not say начали выпить. That sounds wrong because выпить is perfective and refers to a completed whole action, while начать already expresses the idea of the beginning of an action.

For the same basic reason as пирог.

Чай is the direct object of пить, so it is in the accusative singular. Since чай is also an inanimate masculine noun, its accusative singular looks the same as its nominative singular:

• nominative: чай
• accusative: чай

So the form stays чай.

Because и is simply joining two coordinated actions with the same subject:

• мы разделили
• и начали

In a sentence like this, Russian normally does not put a comma before и.

A comma would be more likely if there were separate clauses with more structure, extra inserted material, or a different sentence pattern.

Russian has no articles, so it does not directly mark the and a/an the way English does.

That means пирог can mean:

• a pie
• the pie

and чай can mean:

• tea
• the tea

The exact meaning comes from context, not from an article. In real use, the listener understands from the situation whether the speaker means a specific pie, some pie, tea in general, and so on.

Yes.

The sentence naturally suggests this order:

1. We divided the pie equally.
2. Then we started drinking tea.

That feeling comes mainly from the verb forms:

• разделили presents the first action as completed
• начали introduces the next action

So the sentence is not just listing two random actions. It presents them as a sequence.