Horseshoes (+/-)

Topics: Addition, subtraction, estimation, comparisons.
Materials: Card deck, pencil and paper, white board/document camera.
Grades: 2, 3, 4
Common Core: 2.NBT.B.5, 3.NBT.A.2

How close can you get to the target number with the digits provided?

Horseshoes combines arithmetic practice with complex thinking. Students make their own choices about how to combine the four numbers and get immediate feedback about the effectiveness of their strategies. It’s fun, quick, and can lead to differentiated practice, creative math practice, and also seed interesting conversations about math patterns.

Horseshoes can be played with the whole class, or in small groups. Remove all face cards and tens from a deck of cards, so the only cards are from 1 to 9. The teacher/leader picks out two cards, forms a two digit number with them, and writes it on the board. This is the target number. Then the leader picks four more cards and writes those digits on the board. The goal of the game is to create an equation using only the four digits that were drawn that equals an amount as close as possible to the target. Whoever is closest to the target wins that round. It doesn’t matter whether someone goes over or under. [It is possible to play with multiplication and division, but this version is for addition and subtraction only]

Example Game
The leader draws a 3 and a 7, and writes the target number 37 on the board.
Then the leader draws the four digits 2, 4, 4, and 9.
After all the digits are written on the board, there are three minutes of quiet, where everyone writes their attempts and equations down on their own paper.

When the three minutes are up, the leader calls on people who say what they got, and how they got it.
Student 1: I got 43, by taking 49 – 4 – 2.
Student 2: I got 48. I took 92 – 44.
Student 3: I got 37 exactly! I did 44 – 9 +2.

Horseshoe Golf:

Each player gets points for the difference between their closest number and the target number. The player with the lowest score after 5 rounds wins. In the Example Game above, Student 1 would have 6 points, Student 2 would have 11 points, and Student 3 would have 0, meaning Student 3 is in the lead with the lowest score.

Horseshoes is so interesting to play that you do not need to ask questions to make it more compelling. However, here are some followup questions to consider:

• Is it always possible to reach the target number exactly?
• Is there a way to tell if it is possible to reach the target number exactly?
• Can you use all odd digits to result in an even solution?
• Can you use all even digits to result in an odd solution?