Patricia J. Murphy 
Learning Subtraction with Puppies and Kittens [PDF ebook] 

Math is fun and easy with this delightful text, which teaches elementary students the basics of subtraction through appealing images of puppies and kittens. This book supports the Common Core Mathematical Standards Basic by helping students develop strategies for solving equations within 20, such as counting back or using the relationship between addition and subtraction to understand fact families and double facts. Number lines, fact boxes, and activities enhance the math concepts. A further reading list with books and websites encourages further exploration.