Instead of lecturing my students on calculating a percent of increase or decrease (percentage increase/percentage decrease), as I used to do, I now start class with a mini-lesson (15-20 minutes in length) to go over just the main idea of what they will be learning about today. I include one or two example problems so they get the main idea, and then it's their turn.
As soon as the mini-lesson is over, I set them to task on this worksheet. I use this activity within cooperative groups, and I c