You were sat with your four best friends Mike, Will, Lucas and Dustin in Mike’s basement. Mike and Lucas were rambling on about El and Max, Will was setting up a D&D game and Dustin was helping you with homework.

“Wait so I need to divide x by four..” You say, mainly to yourself, as you tap your pencil against your cheek.

“No. Screw that! You need to start by substituting x and replacing it with 7 and then calculate the area.” Dustin interrupts you. He snatches your pencil and begins to work something out on your sheet. “Don’t speak. I’m calculating.”