The "Doubles and Doubles +1/1" strategy for addition involves adding a number twice or adding two consecutive numbers. It helps simplify addition problems by utilizing known double facts or subtracting 1 from a larger number.
The "Doubles +1" strategy involves using known double facts to derive new facts by adding 1 to them. For example, if a student knows that 4+4=8, they can use this fact to quickly solve 4+5 by adding 1 to the known double: 8+1=9.
The doubles minus 1 strategy is used to add any two consecutive numbers. Students pick the larger number and subtract 1 to find the result. For example, to solve 6+7, a student would pick the larger number (7) and subtract 1: 7-1=6. Then they add the other number (6) to get the final answer: 6+6=12.