What makes a rich, juicy task that can deeply engage learners in thinking and understanding important mathematical ideas? I have found that a great task offers varied entry points, is open-ended, and invites multiple representations.
Hoffer, Wendy Ward
"Tasks that promote problem solving,"
Colorado Mathematics Teacher: Vol. 50
, Article 3.
Available at: https://digscholarship.unco.edu/cmt/vol50/iss1/3