Teachers can tailor this learning activity to three difficulty levels to meet students’ needs. 

• Beginners (6-7 years old): – Learners with low flexibility: The aim of the activity: to reduce anxiety about making mistakes and to make retrying a positive experience. Tasks should be short, clear, explicit and contain limited information. The feedback under the answer tabs should be very supportive and specific (e.g., “Don’t give up! Count the sticks again!”, “Think it through step by step!”). It is also a good idea for the teacher to provide verbal reinforcement from time to time. After finding the correct answer, there can be a short discussion about what helped in solving the problem. The number of tasks can be reduced (e.g., 4 questions) so as not to cause excessive stress.
• Advanced learners (8-9 years old): – Learners with moderate flexibility: The aim of the activity: to develop strategy change and independent use of aids. The complexity of the tasks can be increased (e.g., they require multi-step thinking). Reflective questions can also be included under the incorrect answer tabs (e.g., “What would happen if you tried something different?”, “Would a drawing or calculation help?”). The teacher can gradually withdraw from providing support so that the student can discover the solutions on their own. Feedback should remain positive but encourage independent thinking. The flipbook can consist of 6-8 exercises, and at the end it is worth asking for a short self-reflection: “Which exercise required you to think differently?”
• Experts (9–10 years old): – Learners with high flexibility: The aim of the activity: to reinforce flexible thinking and practice adapting to new situations. The tasks should be varied (text-based, logical, visual, practical) so that students can switch between different thinking strategies. There are no specific instructions under the incorrect answer tabs, but rather self-reflective prompts (e.g., “Why do you think this answer might be correct?”, “Can you think of another way to approach this question?”). The teacher provides help upon request, and the student can decide when to turn the page, thus increasing self-regulation. At the end of the page, students can discuss their own strategies: what helped them adapt quickly, what was challenging.