Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The Abacus: The World's First Computer System + Abacus

The text is poorly written and too much text is spent on explaining ancient counting devices and very little text explaining the abacus. The amount of time spent explaining the use of the abacus itself could be considered an 'epilogue' in back of the book and is completely in error with very poor examples for its operation. It is a shame that this book is still on the market. I do NOT recommend this paperback in spite of the free -- somewhat small -- abacus.