Make charts from a survey, then find the mean, median, mode and range by moving blocks and cards.
Change the survey with + and −, then try each kind of chart.
Share everything out equally: add them up and divide.
The middle number once they are in order.
The number that turns up most often.
Biggest take away smallest: how spread out they are.
The mean shares everything out equally (add up, then divide). The median is the middle number once they are in order. The mode is the number that turns up most often. They are three ways of saying what is typical.
Moving blocks from tall towers to short ones until they are all the same height is exactly what the mean does. Children see that the total stays the same and is shared equally, so add then divide makes sense.
With an even number of values there are two in the middle. The median is halfway between them: for 4 and 6 it is 5.
Tally charts, pictograms and bar charts come from about 6 or 7. The mean, median, mode and range usually come at about 10 to 12.