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Power of Estimation Takes Math Beyond Classroom

MU professor receives lifetime achievement award for contributions to math curriculum

May 28, 2008

Story Contact:  Jennifer Faddis, (573) 882-6217,

COLUMBIA, Mo. – Often, real-life applications of math do not require exact answers. People estimate weekly grocery bills, gas mileage, construction costs and the amount of fabric needed to make a dress. Robert Reys, Curator’s professor of mathematics education at the University of Missouri, has spent much of his career finding better ways to incorporate teaching mental computation and estimation skills into the mathematics curriculum.  

 “Estimation is a very powerful tool in real life,” Reys said. “In many situations, there is no way to know the exact answer, and people have to deal with estimated values. Teachers should help students develop techniques to make estimation more natural for students so math is not seen by students as a set of procedures. Math should make sense, and estimation is a process that makes sense.”

 In his years of research, Reys found that the curriculum at most schools did not include teaching estimation skills, and good estimators usually developed the skills on their own. He also found that students had a particularly hard time estimating with fractions and percentages, which generally reflects a misunderstanding of those concepts.

 Simple estimation strategies can help students catch calculator mishaps, such as pushing the wrong number or symbol. The more confidence students have in their estimation ability, the more likely they will catch errors in calculator results, Reys said.

 “Some teachers are hesitant about allowing students to use calculators,” Reys said, “But, inexpensive calculators have been around for more than 30 years and they are not going away. What’s important is developing estimation skills so students are sensitive to computation errors by having a ballpark idea of what the answer should be.”

 The National Council of Teachers of Mathematics (NCTM) honored Reys with the 2008 Mathematics Education Trust Lifetime Achievement Award for Distinguished Service to Mathematics Education. Reys has written nearly 200 journal articles and written or edited more than 30 books. He has been a member of NCTM, president of the Missouri Council of Teachers, a board member for the School Science and Mathematics Association, chair of the American Educational Research Association special interest group for research in mathematics education, and chair of an Association of Mathematics Teacher Educators task force. He received an MU Faculty Alumni Award in 2004.