Sage and the kids finished that last room where they solved equations with variables on both sides, and now find themselves in a large room with a locked door at the end. Two metal balls sit in the back corners of the room to Sage's right and left, but not exactly in the corners. A sign next to the entrance has an inscription: "To open the next door, you must tell me where the beams of light meet ... without turning on the lasers." It continues: "The first laser is aimed to travel 2 feet...

(by Matthew M. with help from Sage the intrepid student dog) Sage enters the door and sees a vast hall, much bigger than it looked from outside. As he tries to walk past the number line etched into the floor, he is stopped by an invisible force. Sage looks up an sees equations floating in the air involving integers. He wonders if this has something to do with crossing the room. ------------------------------------------------------------------ "Integer operations" just means working with...