This year, I decided I will explore both methods and let students decide which works best for them in certain situations. Since I introduced the number line method with a game, I thought it would be fitting to do the same with chips! This is what I came up with (with the help of my daughter, who came up with some of the rules.)
Witch's Potion Game
- 1 die labeled with 3 addition and 3 subtraction (or a chip that can be flipped)
- 1 six sided die
- Set of algebra tiles or two colored chips. I use algebra tiles that have yellow as the positive and red as the negative...hence the pictures on the game board (yellow brick road for good and red apple for bad.)
- Witch's Potion game board (laminated or in a plastic sleeve)
- Dry erase marker
- Have the chips where both students can reach.
- If desired, you can add in equal amounts of positives and negatives to represent 0 in the cauldron. This way zero pairs will most likely not need to be added immediately.
- Mark the overall charge of the cauldron as 0 on the line using dry erase marker.
- Decide who is going to be the good witch and the bad witch. The good witch can only add or remove the positive chips from the cauldron. The bad witch can only add or remove negative chips. (The only exception to this rule is if zero pairs need to be added...then a witch can add the same number of their chips with the same number of the opponent's chips.)
- Decide on who is going to go first (however works for your kids...I am going to assume good goes first.)
- The Good Witch rolls both the operation and number dice. The operation tells them if they add or remove the number of positives that are revealed on the number die. For example, if they roll "add" and "4", they will add four positives. If they add "subtract" and "4" they will take out 4 positives. After chips are added or removed, adjust the overall charge accordingly.
- The play continues with the bad witch either adding or subtracting negatives and changing the overall charge.
- If at any point a player doesn't have enough of their tiles to take away, they may add enough zero pairs so they can.
Winning the Game
I haven't decided yet on how I'm going to handle this part. I have 2 options:
- If the overall charge gets to 20, the good witch wins, if it gets to -20 the bad witch wins (or any number that seems reasonable.)
- Play for 5-10 minutes and at the end of the time if the overall charge is positive the good witch wins, if it is negative the bad witch wins
I plan on using this game later this week, but I'd love to hear thoughts or feedback!