So, during my recent internet travels I came across this tasty picture.
What questions come to your mind when you see this? I can think of a couple.
Which stack has the second-highest value? Which stack has the lowest-value? (Start with predicting since those are essentially counting by 5s, 10s, and 25s questions.)
Suppose you had three different stacks of dimes and then set them beside three stacks of nickels of equal value. Would there be a consistent height difference? Would the nickels proportionally taller? Would there be no relationship at all?
What questions do you have? What do you think you could do with this? What do you think your students could do with this?