Addition is the Inverse of Subtraction

Purpose:  As a result of this activity, students will be able to understand the inverse relationship between addition and subtraction. 
Related Standard & Benchmarks:  Mathematics   Standard 3.  Uses basic and advanced procedures while performing the processes of computation     Level I [Grade K2]     Benchmark 4. Understands the inverse relationship between addition and subtraction 


Student Product:  An addition problem and a subtraction problem from the same fact family. 
Material & Resources:  Two different colors of manipulatives that can be used to add and subtract (e.g., counting bears, tiles, buttons) 
Teacher's Note:  This activity could be used to introduce or follow up a discussion on fact families. There is a sample worksheet provided at the end of the activity. Using "handfuls" may be distracting for some students so using scoops or small cups to get the manipulatives may be useful. 
Activity 
Have two different groups of manipulatives. For example, use red and green counting bears. Students will take a handful of red bears, count them and write down the red total. Then they will take a handful of green bears, count them and write down the green total. They will use the numbers to write an addition problem. Have them put all of the chosen bears together and count them, this number is the sum of the red and green bears. ___________ + ___________ = __________ 1st handful 2nd handful Sum Now they will write the total number of bears down again on a new line. They will take away the red bears and count them. Then write down the number of red bears that were subtracted. They will use the numbers in a subtraction problem. The students will count the number of green bears that are left. The number of green bears left is the difference, they will write that number down as the answer to the subtraction problem. _______  ___________ = _____________ Total Subtracted Difference The student will see that the two problem they made are inverses of each other. For example: 7 + 5 = 12; 12 – 7 = 5. The student can start over with two new handfuls of manipulatives. Name: _____________________________________________________ Addition is the inverse of Subtraction 1. ___________ + ___________ = __________ 1st handful 2nd handful Sum _______  ___________ = _____________ Total Subtracted Difference 2. ___________ + ___________ = __________ 1st handful 2nd handful Sum _______  ___________ = _____________ Total Subtracted Difference 3. ___________ + ___________ = __________ 1st handful 2nd handful Sum _______  ___________ = _____________ Total Subtracted Difference Download the PDF file. 