Finding the Range
(KS2, Year 4)
How to Find the Range
The range is found by subtracting the lowest number in a set from the highest number.Question
What is the range of the test scores below?Step-by-Step:
1
List the numbers in numerical order (going from the smallest to the largest number).
7 10 8 6 4 → 4 6 7 8 10
2
Find the lowest number in the set.
4 6 7 8 10
The lowest test score is 4.
3
Find the highest number in the set.
4 6 7 8 10
The highest test score is 10.
4
Subtract the lowest number (4) from the highest number (10).
10 − 4 = 6
Answer:
The range of the test scores is 6.A Formula to Find the Range
The formula for finding the range is shown below:In this formula,- xmax is the highest number in the set.
- xmin is the lowest number in the set.
How to Find the Range from a Number Line
Finding the range of a set of numbers on a number line is easy. If we plot the test scores on a number line (with the highest and lowest scores in red), the range is the distance between the highest and lowest numbers on the number line:The range is the distance between the highest and lowest numbers on the number line. In our example, it is 6.How to Find the Range from a Frequency Table
Sometimes data is presented in frequency tables. A frequency table representing the test scores is shown below:It is possible to find that the range of the test scores is 6. finding the range from a frequency table
Beware
Be Careful When the Lowest Number is Negative
Be careful when the lowest number in a set is a negative number. Let's find the range of the following numbers:
−2, 0, 3, 4, 6
The range is found by subtracting the lowest number (−2) from the highest number (6):
Range = 6 − (−2)
Don't forget: Subtracting a negative number is equivalent to adding the (positive) number. (Two negatives make a positive!)
Subtracting −2 is equivalent to adding (+)2:
Range = 6 − (−2) = 6 + (+2) = 6 + 2
Range = 8
Worksheet
This test is printable and sendable