I always like to have math centers available for my students both as an assigned/choice center and also for early finishers.
I created an estimation jar center that is easy to prep and change throughout the school year. I put a variety of objects into an estimation jar. Students can go to the center and estimate how many objects are in the jar. It’s fun to change out the objects to go with a topic of study, season of the year, or a holiday.
The estimation recording sheets can be cut and placed into a math center.