Clear 5 Times

Clearing it 5 times is the most efficient. 5 points for the first ad view, and clearing 5 times gives you 5x5 plus another 5x5 from watching ads, totaling 55 points (5.5 yen). Considering the short time it takes, I think it's quite a good deal. Difficult jigsaw puzzles offer higher points but take a long time, so it's better to do easier ones repeatedly.