24 sets of flashcards to help students mentally add within 100: Add to 12 set of flashcards, Add to 13 set of flashcards, Add to 14 set of flashcards, Add to 15 set of flashcards, Add to 16 set of flashcards, Add to 17 set of flashcards, Add to 18 set of flashcards, Add to 19 set of flashcards, Add to 20 set of flashcards, Add to 30 set of flashcards, Add to 40 set of flashcards, Add to 50 set of flashcards, Add to 60 set of flashcards, Add to 70 set of flashcards, Add to 80 set of flashcards,