Who keeps the fish?

Look for clues that give an exact house: the Norwegian lives in the first house, and the person in the center house drinks milk. Enter what a clue tells you, then combine it with another clue.

Choose a clue from the list or use its arrows to keep it above your worksheet. On a phone, the five house buttons switch between houses. On a larger screen, you can see all five together. The comparison table gives you an overview at any size.

Use each dropdown for a tentative answer. Open Notes for that attribute to cross out values you think are impossible; press a crossed-out value again to restore it. A crossed-out value is your deduction, not an automatic fact. Clear an answer before excluding that same value.

Each value can appear only once in its category. Check reasoning looks for contradictions with the clues and your notes. An unfinished worksheet without a conflict is not proof that every entry is correct. Undo and Redo help you try an idea and revisit it.

Help me reason starts with a nudge. Show the deduction explains one step; Apply this deduction changes your worksheet only when you choose it. The hint system may ask you to fix conflicting entries or notes first.

Your answers, notes, and reviewed clues save on this device when browser storage is available. Print produces a worksheet with all five houses and the clues. Start over asks before clearing your work, and you can undo it during this session.

This fills every answer and ends the deduction challenge. It asks for confirmation first, and Undo lets you return to your own work.