500 Math Crossword Puzzles for Kids, Level 5

500 cross-number puzzles at the Master level — the toughest in the series — mixing decimals, fractions, mixed numbers, and whole numbers across all four operations, for Grades 5–7 (ages 10+). One grid can move between 2.5, 2/3, and 1 1/2 at once, building true number fluency with simple values that stay calculator-free. Every puzzle has a QR code — and a searchable ID — to solve and self-check online for free, no app needed. Large-print, 4 puzzles per page, with a complete answer key.