This Google Slides Activity includes 25 unique slides that help students to find the mean of a set of data using visuals first (stacks of blocks of varying heights), then eventually proving their answer by performing the actual calculations.
The slides become moderately more difficult as students progress through the activity, ending with several decimal problems where the cubes they're working with are split into fourths and the calculated mean is a decimal.
The slides are easy to duplicate or remove to make the activity more/less challenging. The more difficult slides can be removed to easily modify a student's activity, or a teacher could consider some slides "extra credit" or challenge problems to modify for GATE students.
I have used this activity in my 6th grade classroom and all abilities of students enjoyed the challenge. There is no prep required other than saving the activity to your Google Drive and assigning it via Google Classroom or providing your students with a link to the activity.