Step by step
The question
Question: find the range of 4, 9, 2 and 7.
Range of 4, 9, 2, 7
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: 2, 4, 7 and 9.
= 2, 4, 7, 9
We still have 4 numbers.
None is lost.
4 numbers ✓
2 Smallest and biggest
In order, the smallest is first and the biggest is last.
The smallest is 2.
The biggest is 9.
= smallest = 2, biggest = 9
3 Take away
The range is the biggest minus the smallest.
= range = 9 − 2
9 minus 2 is 7.
= range = 7
Let's look back.
First: put them in order.
Then: smallest and biggest.
Last: take away.
Answer
= range = 7