To work out the median of a set of numbers we first place them in order:
1p, 2p, 2p, 2p, 2p, 10p, 10p, 20p, 50p
Then the median is the middle value in the list, in this case 2p.
To work out the mean we must take the total of all the numbers added together:
1p+1p+1p+2p+2p+10p+10p+20p+50p = 99p
and then divide the total by the number of coins (9):
99p / 9 = 11p
so the mean is 11p.
The mode is another way of saying the "most common value" so we are looking for the value that appears most often in the list. In this list it is clearly 2p which appears 4 times.
The range is the difference between the highest and lowest values in the list which are 50p and 1p so the range is:
50p-1p = 49p.
So we have median = 2p, mean = 11p, mode = 2p and range = 49p