This is another gem of a task from Segar Rogers. Segar has insightfully crafted a task which tackles a couple of key ideas: the part whole and ratio meanings of fractions. He scaffolds/exemplifies initially with some diagrams. The other questions leave the space for pupils to generate their own diagrams. After some time we might want to pause the activity on the task to discuss what conclusions we can draw about the relationships between the fractions and if we can think of a method for establishing the missing fraction in each case without drawing. As I often say, the dialogue around the task is just as, if not more important, that the doing of the task itself. It is about brining to attention what awareness have been gathered by members of the class in doing the task.