Try this: Is that ___ too hard right now? Let's take a break and come back to it in 17 minutes.
It sounds random, but a research-based formula for productivity is to work for 52 minutes, break for 17. By taking a break from task-related stress, you come back to it ready to begin again, focussed and more productive than before. The same concept applies to homework, practicing the piano, or playing a sport.