Yes it is a grade level.
a grade 5 is a hard level
Don't hyphenate; ongoing is one word.
You do not hyphenate the number.
I think it's more accepted to hyphenate it.
You hyphenate it only at the hyphen.
You do not need to hyphenate.
It means that you are grade level c witch is 3rd grade
About grade 3.
no its 6th grade level
Ready Level E is typically designed for students in 4th grade. It focuses on developing reading comprehension and vocabulary skills at that grade level.
You would hyphenate "thank you" when it is used as an adjective before a noun, such as in "a thank-you card."