How to use the cheat sheet
Start with the cages that have a single line in this table. Two cells summing to 17 are only 8 and 9. Three cells summing to 6 are only 1, 2 and 3. Pencil those in before you touch a cage that returns eight combinations. The long lists become short once a digit from a unique cage lands in the same house.
Include is for a digit you have already proved must sit in the cage. Exclude is for a digit that cannot, because it is already used in the cage or because every cell of the cage sees it. Both filters apply together. If the table goes empty, one of those claims is wrong, which is a faster bug report than a broken grid twenty moves later.
The same list appears beside the board while you play, struck through when the current grid has ruled a combination out. This page is the printable version of that panel. Teachers and clubs can leave it next to a paper set from the printables.
Read next: cage combinations and the rules.