Fourth Grade: Addition and Subtraction

Play Math War

Grab a deck of cards and play this variation of the classic card game War to practice mentally adding 2-digit numbers. For the game, assign a value of 1 to the aces and a value of 7 to the jack, 8 to the queen, and 9 to the king. The numbers on the remaining cards reflect their values.

  1. Give each player half a deck of cards.
  2. For each round, both players create a two-digit number by turning over two cards. The first card’s value becomes the digit in the tens column. The second card’s value becomes the digit in the ones column. For example, if Player A turns over a two followed by a queen, their number is 28.
  3. Have players compare the two-digit value of their pairs of turned-over cards. The player whose pair has the greatest value gets to keep their cards and their opponent’s only after they add the both numbers.
  4. If both pairs have the same value, both players turn over two more cards and compare the new numbers.
  5. The game continues until one player has collected all the cards or a predetermined number of rounds have been played.

You can also play this game with subtraction. In step 3, find the difference between the two numbers instead of adding them.

Ask your child what strategies they used to add or subtract or ask them to think aloud as they solve the problem. This game is a fun way to practice addition and subtraction skills while also building number sense and mental math abilities.