Why do this problem?
will challenge children to find areas of triangles on a square grid. They do not need to know a 'formula' as they could use the area of surrounding rectangles to help.
What is the area of the tent?
How could you find the area of this triangle?
How could you draw a rectangle around the triangle to help?
Some children might like to draw their own island on squared paper and 'pitch' their own tents.