Sorting Numbers
1 out of 3
Can you sort numbers into sets? Can you give each set a name?
Problem
Numbers can be sorted in many different ways. We are just going to be using the numbers from 0 to 50.
In this box there is a set of numbers:
In this box there is a different set of numbers:
Getting Started
Try choosing two numbers which "go together" to start with. What is the same about them?
What other numbers would go with the first two?
Student Solutions
Samantha from Kaleen Primary School wrote:
1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49
My group is all odd numbers from 1 to 50
Molly from Worfield Primary sent in some different sets:
Odd Numbers between 0 and 25 (half of 50):
1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23 and 25.
And Even Numbers between 25 and 50:
26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 and 50.
I wonder if "between" is the right word to use here? What do you think?
Alex from Sprowston Juniors and Yale from Randwick Public School offered similar sets. Here is Alex's:
Prime Numbers up to twenty: 2, 3, 5, 7, 11, 13, 17, 19
And Yale's:
Again, perhaps "between" isn't quite right?
Finally, Roxy from Burrowmore Primary found a different way of sorting the numbers. She says:
What a good idea, Roxy!
Teachers' Resources
Using NRICH Tasks Richly describes ways in which teachers and learners can work with NRICH tasks in the classroom.
Why do this problem?
Possible approach
Key questions
Possible extension