ACT it OUT

Act it out / Make a model

What Is It?

Two adults and two children have been stranded on an island in a river.They must cross the wide river to safety, but they only have one canoe.The canoe can either take one adult or two children at a time. How can they safely reach the other side?

Understanding the problem

WHAT DO WE KNOW?

There is one canoe. It can hold one adult or two children at a time. There are two adults and two children.

WHAT DO WE NEED TO FIND OUT?

Questioning: How can they safely leave the island? How many trips will it take?

Planning and communicating a solution

WHAT WE DID

Students should label a block for each member of the family – A for each adult and C for each child. Demonstrate for the students how to write down each step, as below,so that steps are not duplicated. Students should create three areas. One for the island, the second for crossing the river and the third for the safe river bank.

Reflecting and generalising

Using blocks to represent the movements of the family members made it easier to work through the steps of the problem and arrive at an accurate answer.

Extension

What if there were five people on the island instead of four (three children and two adults)? What if an adult and a child could fit in the canoe at the same time? How would this affect the speed of moving people off the island?

Independent Task:

WALT - Solve a problem by acting it out or using materials.

GOT it Resource - Problem Sheet 7