Looking on the internet deeply has found these results:

There were 5th graders is the most popular phrase on the web.

There was 5th graders 10 results on the web	There were 5th graders 13 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	Nov 30, 2009 ... There were 5th graders AND high school seniors in the auditorium! Well, the folks at Milwaukee Public Schools have written a blog post about ... Mar 12, 2014 ... Last year there were 5th graders who had their scripts memorized. No way are we going to be outdone by fifth graders!” I mean, come on. Nov 30, 2009 ... There were 5th graders AND high school seniors in the auditorium! Well, the folks at Milwaukee Public Schools have written a blog post about ...

There was 5th graders

10 results on the web

There were 5th graders

13 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

Nov 30, 2009 ... There were 5th graders AND high school seniors in the auditorium! Well, the folks at Milwaukee Public Schools have written a blog post about ...
Mar 12, 2014 ... Last year there were 5th graders who had their scripts memorized. No way are we going to be outdone by fifth graders!” I mean, come on.
Nov 30, 2009 ... There were 5th graders AND high school seniors in the auditorium! Well, the folks at Milwaukee Public Schools have written a blog post about ...