This is a 7 Page Comic that introduces "Mean, Median, and Mode" as three wanted criminals. The pdf also includes 8 separate exercises for each. There is no answer key, that's for you to figure out! This would be ideal for grades 5, 6, or 7.
I'd recommend you start the class with a Do Now in which students are asked to find the sum of several numbers so they develop strategies for working with large data sets. The illustrations are awesome.