In this activity, students will use both math and logic to solve a chemistry themed kakuro puzzle. This puzzle differs slightly from a traditional kakuro by first requiring students to use a periodic table to find the atomic number for each element symbol appearing in the puzzle. Using the atomic numbers as starting clues, students then fill-in the empty squares with numbers 1-9 that sum to the value of the clue, but without reusing any digits. This activity is a fun challenge for students, and provides the opportunity to strengthen logic and reasoning skills.