5×5 Hard Mathdoku 5×5 Mathdoku Puzzles 5×5 Hard 10 puzzles available 🧩 5×5 Hard #1 B → 🧩 5×5 Hard #2 B → 🧩 5×5 Hard #3 B → 🧩 5×5 Hard #4 B → 🧩 5×5 Hard #5 B → 🧩 5×5 Hard #6 B → 🧩 5×5 Hard #7 B → 🧩 5×5 Hard #8 B → 🧩 5×5 Hard #9 B → 🧩 5×5 Hard #10 B →