This is the 53rd most frequent Ukrainian word.
нас
"Us."
In this sentence, 'нас' is part of the phrase 'у нас', used to indicate possession, equivalent to 'we have' in English.
У нас є гарний сад.
We have a beautiful garden.
Here, 'нас' is used as the direct object of the verb 'попросив' (asked), indicating whom the teacher asked.
Вчитель попросив нас допомогти із проектом.
The teacher asked us to help with the project.
In this sentence, 'нас' is used as part of the prepositional object following the preposition 'для' (for), denoting the recipients of the gift.