To get out of maths homework, Josh claims he has number blindness and persuades novice supply teacher Janucek to let him off. When Nathan discovers Josh's dodge, he decides to educate his kid brother himself - though when it comes to numbers, Nathan is as short-sighted as Josh. But at least they can both count the beats when they are rapping.

When Nathan's laptop mysteriously breaks down in the middle of a project, Josh is the obvious suspect. Josh dodges the problem by suggesting Nathan borrows a replacement from the terrifying Miss Andress's IT classroom. But when that laptop goes missing, which of the Carter brothers will end up carrying the can?