Doug Clarke

The Chocolate block task
Ten volunteers are asked to choose which chair they will stand at, knowing that they will share the chocolate with the people who have chosen that chair. Before the last two come on ask audience which chair they would choose and why.
How much chocolate will each person get and how do you know?
Visual model – chocolate lifted in the air so that chocolate – chair the vinculum – people under the chair.

Follow up activities: act out or discuss
1. The case where chocolate is out of the packet and clearly already subdivided. Now using fraction as an operator notion e.g., 1/3 of 24 blocks or 1/5 of 20 blocks.
2. The case where there are more blocks of chocolate at a chair than people.

Three pizzas are shared evenly between seven girls, while one pizza is shared evenly between three boys. Who gets more pizza: a boy or a girl?