Even if you make an effort, you can not always understand a concept. So "to understand" is a task which not guaranteed to complete. When you can not understand, the task becomes painful, and it hurts your motivation. The implicit assumption of "I can understand it" is incorrect. It is better to assume that "I may not understand." When the assumption is incorrect, you feel happy. (Footnote: Finding information is an uncertain task.)

For this type of uncertain task, you can measure its progress with the amount of challenge. Suppose you have to write a report about a subject. If you set the goal "to understand about the subject to write a report," it goes an uncertain task. Instead of that, you can set the goal "to read three books about the subject." This task is achievable with effort. To estimate the time for the task becomes easier. You can keep motivation easier.

Instead of measuring the number of books, you can measure the time. If you set the goal "to read three books for one Pomodoro each," the task can be completed within 2 hours from now.

My favorite task design is to make extracts as pieces of paper (fusen) in limited time. It definitely finishes in time, and after the completion of the task, I get a bunch of fusens as physical proof of achievement. I use those fusens for the KJ method described in the next chapter. #TODO link