Estimation
is a lifelong skill, necessary for the technological society. It helps
students develop flexibility as they work with numbers and measurements,
leading to better judgments about reasonableness and sensibleness of results.
As technology plays a bigger role in their activities, students should
be able to judge whether or not their answer is appropriate with regard
to a range, the number of digits, and the type (whole or decimal number).
Estimation should not be thought of only as rounding. There are many estimation strategies that students naturally use such as front-end, chunking, and special or compatible numbers. Estimation activities should have a context, not the typical "estimate then compute" computation problems. Without a context, students do not develop an awareness of when an estimate is appropriate rather than an exact answer. The context also determines whether an under- or over-estimate is more appropriate.
In grades K4, the curriculum should include estimation so students can