In this feature, we have chosen problems designed to promote a positive attitude to challenging mathematical situations. The article, Getting into and Staying in the Growth Zone is packed with information and advice on helping your students become less anxious and more resilient.
Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?