Here is a big puzzle:
n=9;
hints={{15,Times,{{1,1},{1,2},{1,3}}},{2,Divide,{{2,1},{2,2}}},{2,Divide,{{3,1},{3,2}}},{25,Plus,{{4,1},{5,1},{6,1},{7,1}}},{320,Times,{{8,1},{9,1},{9,2},{9,3}}},{11,Plus,{{4,2},{4,3}}},{5,Plus,{{5,2},{5,3}}},{1,Minus,{{6,2},{6,3}}},{3,Minus,{{7,2},{8,2}}},{45,Times,{{2,3},{2,4}}},{42,Times,{{3,3},{3,4}}},{2,Divide,{{7,3},{7,4}}},{14,Plus,{{8,3},{8,4},{9,4}}},{14,Times,{{1,4},{1,5}}},{80,Times,{{4,4},{5,4},{5,5}}},{5,Plus,{{6,4},{6,5}}},{12,Plus,{{2,5},{3,5},{4,5}}},{14,Times,{{7,5},{7,6},{7,7}}},{45,Times,{{8,5},{8,6}}},{2,Divide,{{9,5},{9,6}}},{2,Divide,{{1,6},{1,7}}},{13,Plus,{{2,6},{2,7}}},{1,Minus,{{3,6},{3,7}}},{1,Minus,{{4,6},{4,7}}},{14,Times,{{5,6},{6,6}}},{6,Minus,{{5,7},{6,7}}},{5,Minus,{{8,7},{9,7}}},{11,Plus,{{1,8},{2,8}}},{3,Divide,{{3,8},{3,9}}},{28,Times,{{4,8},{4,9}}},{4,Divide,{{5,8},{5,9}}},{11,Plus,{{6,8},{6,9}}},{3,Minus,{{7,8},{7,9}}},{5,Minus,{{1,9},{2,9}}},{1,Minus,{{8,8},{9,8}}},{1,Minus,{{8,9},{9,9}}}};
AbsoluteTiming[
cands=ConstantArray[Range[n],{n,n}];
old=False;
While[old=!=cands,
old=cands;
ApplyHint@@@hints;
NakedSubset/@Range[n];
If[old==cands,
BoxBoxInteraction[];
];
];
]
DrawGrid[cands,hints]