Cage Remainder
Beginner Places a digit Used in: Killer Sudoku, Kakuro
A cage or run has a fixed total. When only one cell is still empty, its value is simply that total minus the digits already placed — a group summing to 15 with a 6 and a 4 must finish with a 5. The same move is called Cage Completion in Killer Sudoku and Run Total in Kakuro.
How to spot it
A cage or run with exactly one empty cell left.
What you can conclude
Subtract the placed digits from the cage or run total — that is the missing cell.
Worked example
A 15-cage already holding 6 and 4 must finish with 15 − 6 − 4 = 5.