Essentials class. It may have a real name, but we've resorted to calling it Hi-Lo. It emphasizes multi-digit adding and subtracting as well as regrouping and borrowing.
To begin, remove face cards and 10's from a deck of playing cards.
Each player starts with five playing cards. Of the five cards, make the two highest numbers you can with four of the cards. Discard the extra card. Add the two high numbers together.
Each player now receives three cards. Make the smallest number you can with two of the cards. Discard the extra card. Subtract the low number from the sum of the first problem.
Each player now receives three more cards. Make another high number with two, discarding the extra card. Add that number to your previous total, and you have your score.
Usually we play about five rounds to determine a winner. For extra fun, we add the total of the five rounds together, and take an average (to work some division into the game!)