Sticky notes got their start nearly 40 years ago, when 3M introduced the now-classic yellow Post-it Notes. In the years since, their popularity has skyrocketed, and they’re now available in every shape, size, and color you can imagine. They have endless applications, especially in schools; teachers use sticky notes for math, reading, art, planning, and so much more. Here are 25 clever ways to use sticky notes in the classroom.