National Council of Teachers of Mathematics
The Math Forum: Fermi Questions
This tutorial from the Math Forum provides the approach to problem solving made famous by Enrico Fermi. Fermi, a brilliant Italian physicist, used estimation frequently in problem-solving.
AAA Math
Aaa Math: Estimating a Sum by Rounding
This site explains how to estimate sums of whole numbers. Gives practice and games to practice this skill.
AAA Math
Aaa Math: Estimating a Difference
This lesson explains how to estimate differences between whole numbers. Gives practice and games to practice this skill in a helpful and fun way.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Estimation Contest
A lesson plan that teaches the power of estimation and its uses, a distinction between estimation and guessing.