This Intro to Adding/Subtracting Rational Numbers activity & project also includes:
How can you add two numbers and arrive at zero? Use negative integers! Assign each group a different problem to solve as a team. The lesson plan says to have them use Geometer's Sketchpad® to check their answers, but if you do not have this software, you could have the groups trade problems to correct each other's. In the end, you will use the problems to demonstrate how p+q is equal to |q| from p, thus meeting one of the seventh grade math Common Core standards. Note that this resource does not provide the answers to the assigned problems or a homework assignment even though it is suggested.