Killer Sudoku Rules

Welcome to this video that explains the rules of killer sudoku puzzles. You can play the example puzzle here:

The video outlines the rules of killer sudoku, placing 1-9 once in each row, column and 3x3 box and explains how the dashed-line cages work, namely that their contents must sum to the digit given at the top-left of each caged region and that numbers cannot repeat within them.

The video then has a brief look at how to solve the puzzles, noting that some totals such as 4 from two squares and 23 or 24 from 3 squares can only be solved in one way, and hence the pencilmarks can be written in. The video then places a few digits in the grid before suggesting the viewer may wish to then have a go at completing the rest of the puzzle themselves as practice solving a killer sudoku puzzle.