Looking for no-prep math homework, classwork, workstations, or sub plans? These riddle math activities will reinforce your students' understanding of finding ten less or ten more. These worksheets have holiday and seasonal themes: HALLOWEEN, AUTUMN, THANKSGIVING, CHRISTMAS, WINTER, HAPPY NEW YEAR, VALENTINE'S DAY, ST. PATRICK'S DAY, EASTER, SPRING, and SUMMER! The answer keys are provided. CLICK ON EACH PREVIEW TO SEE THE FULL RESOURCE. Each correct math answer reveals a letter, unraveling th