Aleh and Elena, EXPERIENCES. Anytime there's talk of an exchange in English, the thing exchanged is plural: I need to change jobs, my children are swapping cars, the kids are trading baseball cards, etc.

+Валерий

to Uly: What notes have to do with expetience?

It's actually more correct and common to say "compare notes." It's an idiom that means to share your experiences with somebody and they share their experiences with you. The underlying idiomatic premise is that you both took notes during your experience and you're going to share them with one another.

Thank you, Uly. I thought that since "experience" was uncountable "singular form " was correct

Except that it's not uncountable. It depends on the context. When you talk about the experience that you bring to a new job, it's uncountable. But when you talk about events in your life, it's countable: I had three life-changing experiences on my last vacation: I met my husband, I lost 30 pounds, and I learned French.

Still it's strange ;). We don't exchange the events, we exchange our knowledge. If it were not you, I'd have never guessed it should be plural here.

You're right, you don't exchange the event, you exchange your impressions of the event. That's the other meaning of "experience" – your impression of what you did: Tell us about your experiences on this trip. (= your impressions about the things you did and saw)