There weren't as many people as I thought there "was" going to be.
vs
There weren't as many people as I thought there "were" going to be.

Which is correct? Both are fine to use?

See a translation

@o_o9

Sorry, let me explain it a little bit more.

“wasn’t” is a connected word of “was not”.

“People” is singular, although it is about many people. It’s the same with the word “everyone”.

“were” is used when the word in front of it is plural.

E.g. They WERE happy.

“was” would be a better choice as it is used when the word in front of it is singular, like “people”.
E.g. I WAS happy.

English can be confusing, especially with words that are plural and singular. Example, the word “you” is considered plural in english. I don’t know why either 😅 so behind “you” should be “were”.

E.g. You WERE happy.

But both is fine.

And I’m sorry but I don’t understand what you mean by “agree in number” 😅

I hope this helped you understand it a little more!