These situations represented zero pairs. I passed out red beans and white beans to the students. The red beans represented negative numbers and the white beans represented positive integers. Each student was given 10 red and 10 white beans and a strip of paper with four expressions. Using zero pairs and the beans, they had to model the expression using the beans, combine all zero pairs that they were able to, and record what was left. I posed a guiding question: Using the beans, what makes a zero pair? They took two minutes to analyze their expressions and answers. They had to come up with an explanation of what happened when certain signs came together. They were able to come up with the algorithm for adding/subtracting integers without me telling them. Using this hands-on lesson, they discovered it on their own!
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