These have been specifically assigned to your child during band/string class, but by all means, let them play ahead if they want and are able! My favorite part of the day is when a child shows me something new they learned all by themselves! :)
At a minimum, your child should be practicing what's listed, but please encourage them to take the initiative to do even more. All students should be playing at home 4-5 days a week, 15-20 minutes each practice/homework session.
W= Warm-Up exercise for the next lesson
R= Exercise (s) that need to be reviewed for the next lesson
HW= New exercises to work on for the next lesson
T= Exercise you will be tested on
EC= Extra Credit