Doing wanted posters for numbers is a great way to have kids think about specific properties of particular numbers. The posters make a great display, too — and I am always looking for ideas for math bulletin boards!
The idea is useful at lots of grade levels. You could have older students choose a proper fraction (e.g., 5/8), a mixed number (e.g., 4 1/3), or a square or cube root (e.g. the square root of 50).I wrote about these posters before — click here for the link to the previous write-up where you can download the template.
Give them a try and send me a picture of your display!