The mean and handling data · Year 6
In The mean and handling data (Year 6) you practise 3 skills: Finding the mean · The missing value · Properties of the mean. The mean is what each one gets when everything is shared out equally. To find it, add all the values and divide the sum by how many values there are. For example, the mean of 4, 6 and 8 is 18 divided by 3, which is 6.
When you know the mean and how many values there are, you can find the sum: the mean times the number of values. That is how you find a missing value. The mean is always between the smallest value and the largest, but it does not have to be one of the values, and it does not have to be a whole number. A new value changes the mean: a value bigger than the mean pulls it up, and a value smaller than the mean pulls it down. Adding a 0 pulls the mean down, too. Tables and charts sometimes hold very big numbers. A million is a thousand thousands, and a billion is a thousand million.
Tip: Before you divide, count the values. A 0 is a value too, and it counts.
What you learn
Finding the mean
For example: What is the mean of the numbers? 6, 13, 7, 14
Answer and solution
The answer: 10
6 + 13 + 7 + 14 = 40 40 ÷ 4 = 10 The mean is 10.
The missing value
For example: The mean of three numbers is 14. Two of them are: 20, 4 What is the missing number?
Answer and solution
The answer: 18
14 × 3 = 42 20 + 4 = 24 42 − 24 = 18 The missing number is 18.
Properties of the mean
For example: The mean of these numbers is 11: 16, 7, 13, 8 The number 11 is added to the list. What happens to the mean?
- It goes up
- It stays the same
- It goes down
Answer and solution
The answer: It stays the same
The new number is equal to the mean, 11, so the mean stays the same. 44 + 11 = 55 The new mean is 55 divided by 5, that is 11.
The exercises are made by rules and the answers are worked out in code, so there are new exercises every time. The topic follows the national curriculum in England: mathematics (key stages 3 and 4).