Addtion Doubles Game +1 - 1 Strategy

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 The Doubles +1 or −1 Strategy game helps students build fluency with near doubles addition facts such as 6+7, 8+9, and 7+8 by connecting them to doubles facts they already know. Instead of relying on counting strategies, students learn to ask a powerful question: Is there a double hiding in this problem? Once they identify the known double, they can simply add one more or take one away to find the answer. Research shows that these types of derived fact strategies help students move beyond counting and begin using relationships between numbers to solve problems more efficiently. When students use known facts to derive new ones, they reduce cognitive load and strengthen number sense, which is an important step toward long term fact fluency (see research on addition and subtraction fluency from Meaningful Math Co: https://www.meaningfulmathco.com/addition-and-subtraction-fluency/ and research on children’s use of derived fact strategies: https://pmc.ncbi.nlm.nih.gov/articles/PMC3880841/).

The game is structured across three levels to gradually build understanding and independence. In Level 1, students identify which double fact is hiding inside a near doubles problem, supported by a visual dot model that shows the two rows lined up side by side. In Level 2, students apply both the +1 and −1 strategies to the same problem while still using the visual model as a guide, helping them see how small changes to a known double create a new fact. By Level 3, the visual supports are removed and students solve near doubles problems using numbers only, demonstrating that they have internalized the strategy. This progression from visual models to abstract reasoning reflects what research consistently shows about how children develop mental math strategies and flexible number relationships (see the research summary on addition strategy development here: https://www.meaningfulmathco.com/addition-and-subtraction-fluency/ .