Calculation exercises: when you need to give up

Typically, we never want to give up. That is, we really want to find the solution to the puzzle before looking at the solution. Otherwise we lose the educational value from the puzzle.

But when we've spent as much as time as we would like (for each person it's different, for me sometimes it's up to 24 hours) but still are not 100% positive on the solution, we decide that we need to move on. 

I suggest at this moment to not directly look at the solution, but to first write down your intended solution, the moves and the plan, and then compare that to the correct solution. This way we can still salvage some educational value - in that we can try to discover where our thought process went wrong and make the necessary adjustments when comparing to the right solution.

 Perhaps you already do this - then keep it up! For those who aren't already doing this, hopefully this helps