Mr. Watt,
I just wanted you to know that I am using Check Digits with my third grade class and it is the best thing that I have seen come along in math since I've been teaching. I share it with everyone I know and their amazement has been the same as mine. Not only is this a good method for checking work, but it helps the children practice addition and subtraction facts. My kids will borrow from a number or add to a number to make it a 9. Thank you again for coming up with this great method to check your work.
                                                                                   B. H., Elementary Teacher
                                                                                               Bluffton, SC
Dear Mr. Watt
I want to thank you for writing this book.  It has helped my daughter Vicki very much.  Letís just say she was a D and F student in 4th, 5th, and 6th grade.  Now she is a 7th grader and she made the honor roll in math, and she is now doing Honors 8th grade math.  She loves math and wishes you made other books.  If she is confused about something she will look over the book and see if it can help her before she runs to the teacher.  I am personally glad you made this book, for I am not good in math and have NO idea how to help her in this type of math.  I know its going to get harder and I hope you will make more to help her along when she enters high school.
Thank you again.
Irene P.
P.S. She was also asked to enter this math competition in Morris in a few weeks for her school .
Letter from one homeschooler to another forwarded to us at Back Fence Publishing.
from Delaware Classical Home Educators' Network  
Don't know if you remember me or not, we've met at skating and other homeschooling events before. Anyway, I just wanted you to know that I bought this book after reading your message and info at the website and so far we are VERY pleased with it. It is really amazing how it works!! My daughter even likes the lessons and is already (after only one week!) doing better in math!
Thanks so much for sending this info!!!
Dear Mr.  Watt, 
A fellow home-schooler shared about your book & we just wanted you to know that it is already making such a difference. THANK YOU SO MUCH! I have been spreading the word. My daughter is 15 & has many learning differences.  She caught on quickly and is feeling much better doing math.  We have had many high fives, especially with multiplication of hundreds which has always been so frustrating.  Can't wait to try division.  I can't thank you enough!  
Many blessings,                                                         
C. Dunn, Delaware
Bill Petersen is a retired high school math teacher and currently coaches the Naperville North High School Math Club in Naperville School District 203.  The Naperville, IL school system has been rated as the top school district in the United States for math and is continually rated in the top 95% of national testing.   Mr. Petersen is a 2005 recipient of the Mathematical Assoc. of America's Edyth May Sliffe Award for Distinguished High School Mathematics Teaching .   
Mr. Petersen calls Eliminating Careless Error "amazing" and says, "It allows you to simply check the four main areas of adding, subtracting, multiplying and dividing and is laid out in a way I feel is easy to understand. I think the book helps erase the 'ugly monster' some see math becoming and helps kids have success, which is the key." (from local newspaper article, NAPERVILLE SUN, JULY 31, 2006, David Sharos - click on link below for full article).
"The book Eliminating Careless Error is a welcome and long overdue addition to the general library of mathematics resources.   A child learning this method will find that all numbers follow a few simple geometric patterns.  They will begin to understand there is an important element of simple form within basic number theory that is currently missing from primary educational material.  The method is presented clearly and in an entertaining manner.  It is complete, with guidelines for instructions, exercises, and sample problems.  Parents can feel confident teaching this method to their children with this book." - Dr. James E. Bennett, Ph.D. Mathematics.