Additional Math Pages & Resources

Tuesday, September 1, 2009

The Error. The Mistake. The Prize.

To err is human. Perhaps. But it's the curse of a math editor.

An error is a failure to be correct. Many things cause errors. Some are out of your control. For example, if you haven't learned to add, you are likely to make math errors.

A mistake is an error caused by bad judgment or carelessness. You might have avoided the error. For example, once you have learned addition, you know 2 + 3 = 5. But if you don't pay attention, you may get it wrong.

My sister has a PhD. in Reading Education. She loves to cook. I asked about her big dinner Sunday night. She replied, "I didn't notice the recipe said I had to simmer the mixture for 3 hours ..." Oops. And she knows how to read.

Here at AnsMar publishing, we do make a few errors. Some are based on mistakes in wording, and spelling, and translation. Others are math mistakes. We know that we should phrase questions clearly, do math perfectly, keep answers on separate layers in the files, compose pages and screens properly, then translate equivalently. Without mistakes. But we still make a few errors.

Some people have suggested we switch on the automated error detection and correction system, thinking we have the mathematical equivalent of a spell checker! Well, there's no such thing.

However, we do have a student-powered error detection and correction process in Excel Math called the CheckAnswerTM. It works like this:

We arrange a set of 3-5 problems on the Lesson Sheet. The sum of the answers is shown nearby. Students solve the problems, add the answers, and compare their sum to the CheckAnswer. If the numbers don't match, they look for errors. Usually they made the error - but sometimes we did.

Sadly (for us), the CheckAnswer adds another layer of complexity. We create about 6,000-8,000 math problems per grade. Besides putting those problems into a smoothly-spiraling presentation, we also create and verify several thousand CheckAnswers. We now have more chances to make mistakes. But then we give students an excellent tool for locating those mistakes AFTER we publish. Sigh.

I hope it wasn't a mistake to try to explain math errors!

We sometimes hear, "It's not getting a correct answer that's important, it's learning multiple ways to explore the question."

I think, "Really? Explain that to the IRS. Or to the board you just cut too short."


Here is a problem. Find the right answers  and show how you found them.

Sarah ran a race in 37 seconds. Jane took 8 seconds less than Sarah but 4 seconds more than Celia. How long did it take Celia to finish the race? What is the finishing order and who won?

The first 3 correct answers (with work) that I receive will each win an Excel Math Projectable Lessons CD worth ≈ $50. You need to have a mailing address in North America in order to receive this prize.


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