Mean, median, mode, and range: find the missing number
key notes:
The mean is the average of the numbers. You find the mean by adding the numbers together and then dividing by the number of numbers in the group.
The range is the difference between the greatest number and the least number.
Learn with an example
➡️ Dan has the following data:
16 m 19 20
If the mean is 18, which number could m be?
- 17
- 5
There are 4 numbers in the group.
Try m = 17.
Find the sum of the numbers.
16 + 17 + 19 + 20 = 72
Divide by 4.
72 ÷ 4 = 18
When m = 17, the mean is 18.
Try m = 5.
Find the sum of the numbers.
16 + 5 + 19 + 20 = 60
Divide by 4.
60 ÷ 4 = 15
When m = 5, the mean is 15.
The mean is 18, so m = 17.
➡️ Nicholas has the following data:
15 s 17 13 20
If the range is 7, which number could s be?
- 1
- 16
Try s = 1.
Arrange the numbers from least to greatest.
1 13 15 17 20
Subtract the least number from the greatest number.
20 − 1 = 19
When s = 1, the range is 19.
Try s = 16.
Arrange the numbers from least to greatest.
13 15 16 17 20
Subtract the least number from the greatest number.
20 − 13 = 7
When s = 16, the range is 7.
The range is 7, so s = 16.
➡️ Zach has the following data:
20 20 18 12 n 17
If the range is 8, which number could n be?
- 8
- 19
Try n = 8.
Arrange the numbers from least to greatest.
8 12 17 18 20 20
Subtract the least number from the greatest number.
20 − 8 = 12
When n = 8, the range is 12.
Try n = 19.
Arrange the numbers from least to greatest.
12 17 18 19 20 20
Subtract the least number from the greatest number.
20 − 12 = 8
When n = 19, the range is 8.
The range is 8, so n = 19.
Let’s practice!🖊️
