Find Change +/-

Finds the missing addend (e.g., 5 + _ = 7 or 9 - _ = 3) to solve Join and Separate, Change Unknown problems by adding on or taking away objects. Compares by matching in simple situations.


You may see this:

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Other Examples:

  • Join-to, count-all groups: Asked, "You have 5 balls and then get some more. Now you have 7 in all. How many did you get?", counts out 5, then counts those 5 again starting at 1, then adds more, counting "6, 7,", then counts the balls added to find the answer, 2. Some children may use their fingers, and attenuate the counting by using finger patterns. 
  • Separate-to, count-all groups: Asked, "Nita had 8 stickers. She gave some to Carmen. Now, she has 5 stickers. How many did she give to Carmen?", counts 8 objects, separates until 5 remain, counts those taken away. 
  • Match, count rest: Asked, "Here are 6 dogs and 4 balls. If we give a ball to each dog, how many dogs won't get a ball?", counts out 6 dogs, matches 4 balls to 4 of them, then counts the 2 dogs that have no ball. 

Help your student become a(n) Find Change +/-

These activities challenge children to solve  addition and subtraction problems that go beyond the typical "result unknown" type. They find the missing change in Change Plus (Join) problems (e.g., 5 + _ = 7) and Change Minus (Separate) problems (e.g., 9 - _ = 3) usually using objects, including fingers. They also solve static Collection, or Part-Part-Whole, problems when a part is missing.

Special Thanks To

Institute of Education Sciences
The research reported here was supported by the Institute of Education Sciences, U.S. Department of Education, through grant numbers R305K050157, R305A120813, R305A110188, and R305A150243. to the University of Denver. The opinions expressed are those of the authors and do not represent views of the Institute or the U.S. Department of Education.