Digit Dog and Calculating Cat have some yellow and purple stars to put on their tree. They can only put 5 stars on the tree and have to decide how many of each colour they use. How many different ways can they do it?
What has Digit Dog done? What is Calculating Cat thinking?
How many different ways do you think they can put the stars on the tree? Why do you think that?
How are you going to record your different ways? How will you remember what you have done?
How do you know you have found all the different ways? Convince me.
Have you found any patterns?
Look for children who are starting to organise their work and systematically look for all the combinations. The activity is about exploring the combinations and reasoning about choices and patterns.
Ways to record
Provide enough stars and trees so that each combination can be kept and checked. Children can then look at all the trees and say what is the same and what is different. Ask them to put the trees in order and look for a pattern.
Have number sentences on card and ask children to match the number sentence to the trees.
What does the 5 represent? – it is the 5 yellow stars. The 0? – there are no purple stars.
Write number sentences for each tree on separate post-it notes. These can then be sorted and put in order.
Use Numicon shapes to represent the number pairs.
There was a different number of stars on the tree? Explore any number.