Step by step
The question
Question: find the range of 15, 3, 11, 8 and 20.
Range of 15, 3, 11, 8, 20
The range shows how spread out the numbers are: the biggest minus the smallest.
range = biggest − smallest
1 Put them in order
First we put them in order, smallest first: 3, 8, 11, 15 and 20.
= 3, 8, 11, 15, 20
We still have 5 numbers.
None is lost.
5 numbers ✓
2 Smallest and biggest
In order, the smallest is first and the biggest is last.
The smallest is 3.
The biggest is 20.
= smallest = 3, biggest = 20
3 Take away
The range is the biggest minus the smallest.
= range = 20 − 3
20 minus 3 is 17.
= range = 17
Let's look back.
First: put them in order.
Then: smallest and biggest.
Last: take away.
Answer
= range = 17