Learn Hardcore Russian: Давайте не забудем спросить о скидке. - Let’s not forget to ask about the discount.

Давайте is the standard way to say “let’s” in Russian. It’s an imperative form that includes the speaker and at least one other person, inviting everyone to do something together.

How can не забудем (future tense) function as an imperative here?

Literally не забудем is the 1st-person-plural future of забыть (“to forget”). But when you put it after Давайте, it takes on an imperative flavor: Давайте не забудем = “let’s not forget.” This construction is very common for polite group instructions.

Why is the verb спросить in the infinitive after не забудем?

In Russian, when you have one verb conjugated (here не забудем) expressing obligation or intent, any following action verb appears in the infinitive: не забудем (what?) спросить = “let’s not forget (to) ask.”

Why do we say спросить о скидке instead of спросить скидку?

спросить о + Prepositional means “ask about something” (inquire, get information).
спросить + Genitive is not used. To “ask for a discount” (i.e. request it), you’d use попросить скидку (ask someone to give you a discount).

What case is скидке, and why?

Скидке is in the prepositional case because of the preposition о. When you “ask about” something in Russian, you use о + Prepositional.

Could we replace “Давайте не забудем спросить о скидке” with Давайте спросим о скидке? What’s the difference?

Yes, you could say Давайте спросим о скидке (“let’s ask about the discount”). The difference is:

Давайте спросим is a direct suggestion to ask right now.
Давайте не забудем спросить emphasizes you might forget, so “let’s remember to ask” (perhaps later, in the process).

What’s the nuance between не забудем and не забывайте?

не забудем is perfective future (one-time warning: let’s not forget).
не забывайте is imperfective present imperative (keep not forgetting / make it a habit).
Here you want a one-off reminder, so the perfective не забудем is more natural.

How would you say this to just one person, informally or formally?

Informal singular:
— Давай не забудь спросить о скидке.
Formal or plural:
— Пожалуйста, не забудьте спросить о скидке.