This butterfly math book is a great way for children to learn and practice their addition skills from eleven to twenty (11-20). The child places the number card on each butterfly addition card. (You can laminate it and have the child write on the card.) The child can use the 20 butterfly counters if they need extra help. There are 165 butterfly flashcards plus number cards 11-20. It makes a great math center while doing a spring theme unit or butterfly theme unit.