The object of Pyramid is to match 2 cards that add up to 13. King is worth 13 (you can just click a King to clear it without matching it), Queen is 12, Jack is 11, and Ace is 1. Below is the list of pairs that will work. The suit does not matter, just the number. Clear the board 10 times for this achievement. You can clear the board multiple times in 1 game.
King = 13
Queen + Ace = 13
Jack + 2 = 13
10 + 3 = 13
9 + 4 = 13
8 + 5 = 13
7 + 6 = 13
Clear the board 100 times to unlock