This activity allows students to be teachers too. I have students choose a partner. The purpose of this activity is to separate the partners, each learning a different way to add integers, then require them to come back together to teach each other. I time 15 minutes to learn it, 10 minutes for one to teach, then 10 minutes for the other to teach. Timing allows for whole group discussion and clean up before class is over. Manipulatives needed are integer chips (red on one side, yellow on the other), and number lines (I print copies of number lines, put them in clear sleeves, then students use them with dry erase markers).