Count the number of sides and corners on each of the shapes. Shape A, B and D all have 4 sides and 4 corner. Shape C is a triangle. It has 3 sides and 3 corners, so it is the odd one out.

What children are less likely to learn is that all the shapes in the world have not yet been discovered, a strangely moving fact that Amy Alznauer discusses in “The Five Sides of Marjorie Rice.” ...