If you can get hold of a cash tray it would be good to actually be able to handle different coins/notes in your own currency.
The children can sit round such a tray and talk with you about what there are most/least of in the tray and how they would go about finding out.
Once they have explored, you can introduce the mathematical vocabulary of 'mode', if appropriate.
How did you find the mode?
Challenge children to change the mode of the set, for example, you could ask "what would have to happen for the . . . . . . to be the mode (choose another coin/note that does not represent the mode at the start)?"
Handling real money will help all children access this activity.