After teaching sixth grade for almost 20 years, I have found that proportions are the KEY! You can use proportions to solve a LOT of concepts in sixth grade. Percents and proportions go hand in hand.
This page is meant to go into their math or interactive journal.
This sheet shows how to use proportions to solve problems involving, "is", "of", and %'s.
I hope it work for you and your class as much as it helped mine!