Office Pyramid Solitaire
You remove cards by creating pairs of 13 in face value. You can use every card that's not under another one. Pairing suited cards gives double the points! A king (value of 13) is removed just by clicking. Ace is valued at 1. You can deal new cards by clicking the deck on the bottom right. Note that the draw deck is not reused after the last card was dealt on any difficulty.
About this game
Office Pyramid Solitaire has one objective: clear the card pyramid, matching pairs that add up to 13, until nothing is left.
Each pair you remove must total 13: a king goes alone, a queen pairs with an ace, a jack with a two, and the number cards follow the same math down the pyramid. Only uncovered cards are in play, so the order you click matters more than the luck of the deal. The office theme keeps the visuals light, like a desk toy between tasks. On hard difficulty you also have to empty the draw deck, which turns a coffee-break game into a planning exercise. One deal takes about three minutes.
Reading the pyramid before making your first move usually beats clicking the first legal pair you spot, since uncovering the wrong card early can leave a cluster of high-value cards stuck under something you can no longer reach. On hard difficulty especially, planning which cards to clear first, rather than working left to right, tends to open up more of the draw deck by the time you actually need it.
Cards buried near the bottom corners of the pyramid are usually the ones worth clearing first when more than one legal pair is available, since they tend to unlock the most additional cards at once.
Office Pyramid Solitaire is unblocked and works fine on a school Chromebook, so it is an easy, quiet pick for a short mental break between classes. WTF Games has more card and brain games in the Puzzle & Brain category if this kind of quick math-and-memory challenge is what you are after.