Posted by: degarcia | April 2, 2009

Big Idea: Estimation

Big Idea: Estimation Posted by Courtney Butikofer

ESTIMATION: Numerical calculations can be approximated by replacing numbers with other
numbers that are close and easy to compute with mentally. Measurements can be approximated
using known referents as the unit in the measurement process.

Estimation in a necessary skill for students to master because it is very useful in everyday calculations of all kind.  Below are some examples of where estimation is used and therefore needs to be taught to students.  Estimation is often taught closely tied to rounding, which students often have a difficult time with.   I will be providing resources and links that support, explain, and allow practice for both estimation and rounding.

Examples of Mathematical Understandings:
• The numbers used to make an estimate determine whether the estimate is over or under the exact answer.
• Division algorithms use numerical estimation and the relationship between division and multiplication to find quotients.
• Benchmark fractions like 1/2 (0.5) and 1/4 (0.25) can be used to estimate calculations involving fractions and decimals.
• Estimation can be used to check the reasonableness of exact answers found by paper/pencil or calculator methods.
• Length, area, volume, and mass/weight measurements can be estimated using appropriate known referents.
• A large number of objects in a given area can be estimated by finding how many are in a sub-section and multiplying by
the number of sub-sections.

Links to great Estimation and Ronding Resources

Great comprehensive website with definition’s and explanations of each specific kind of estimation and rounding found in the core.  Look here first to build adequate background knowledge to teach these concepts well.

Interactive Websites and Games with Estimation

Scroll down to find the estimation activities on this website.

Scroll down to Concept Number Eight on this website to access lots of great rounding and estimation resources and activities.


Charles, R.I. (2005).Big ideas and understandings as the foundation for elementary and middle school mathematics. Journal of Mathematics Education Leadership. 7, 1-16.

All websites listed as themselves.



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