Yeah, I wouldn't worry about it. Last year at the very start of the year, DS7 brought home a bunch of silly sheets of math and I just printed him out some multiplication and division problems to do instead and sent that back; I saw the teacher the next day or so, and she laughed and said not to worry about the silly stuff, it was just habit for her to give it to everybody.
If 5th grade math hasn't started yet, it was probably just habit or absentmindedness of the teacher. I need to check and see when our 5th grade math class starts this year, too!
