Although this book does have a lot of good activities, there are many blatant errors and laziness on the author's and editor's part. For example, Page 21 has addition of three digit numbers, and page 13 has addition of decimals. The problems are exactly the same except for having 2 more problems added in and decimals added to the problems. On page 70 and 72, 6 out of the 10 problems are repeated. On page 105, Problem three, is answered incorrectly in the answer key and has two right answers. On page 126, Problem 19 does not match up with a right answer. 56/4 does not equal 14x4. Although this book is a good tool, it needs to be edited again.