April Fools' Day Math Puzzle for Grades 1-6 — Mashup Math Today's April Fools' Day Math Challenges for grades 1-6 are sample puzzles from the best-selling workbook: The Big Book of Super Fun Math Puzzles for Grades 1-6. The activities are tiered by difficulty using the following system: Pink Level (Grades 1-2) | Blue Level (Grades 3-4) | Green Level (Grades 5-6+)