From a Washington Post article, Math Educators Find Common Denominator:

The program [Everyday Mathematics] is being used in many schools across the country, including Annandale Terrace Elementary School. On a recent day at the Northern Virginia school, teacher Abigale Braun presented this problem for 21 second-graders to solve: 15+5+9=__. Then she asked them how they got their answers.Dennis Segovia-Ramirez said he put 15 plus 5 together to make 20 and then added 9. Sarah Velegaleti said she knew 5+9 was 14 and just added 15. Laila Elahi put down 15 tally marks on her white board, then 5, then 9, and added them all up.

Braun praised them, telling them that there was no single correct method and that it was important for them to figure out the way that worked best for them.

OK, fine. There's no single correct method - although both Dennis and Sarah are using the associative property of addition [ (x + y) + z = x + (y + z) ] to solve the problem.

But Laila's method was badly wrong, even though she came up with the right answer. Counting things out the way she did is infinitely more time-consuming and prone to error. I hope that one of her parents notices and gets her math help before she falls hopelessly behind.

UPDATE: Looks like the Washington Post author may not have been providing the full story. Ms. Braun left the following in the comments:

*I am the teacher whose class is featured in this article. The information in the article only represented part of the lesson. What was not included in the article was the class discussion we had about why Leila's method would not be practical. We talked about what would happen if the question was something like 43+98+65. Then it would be extremely time consuming to make tally marks, and as you stated, very prone to error. She then used the associative property to solve the problem as most of the other children did. Thank you for your comments.*

So it sounds like Ms. Braun is the sort of teacher that Leila needs.

Posted by jeffreyb at December 29, 2004 01:37 PMComments

I am the teacher whose class is featured in this article. The information in the article only represented part of the lesson. What was not included in the article was the class discussion we had about why Leila's method would not be practical. We talked about what would happen if the question was something like 43+98+65. Then it would be extremely time consuming to make tally marks, and as you stated, very prone to error. She then used the associative property to solve the problem as most of the other children did. Thank you for your comments.

Posted by: Abigale Braun at January 28, 2005 07:57 PMPost a comment