These instructional materials were produced as part of the project, Developing Computational Estimation Materials for the Middle Grades. The introduction to these eighth grade materials covers the following: why teach estimation; how the materials were developed; and how the lessons are organized. The 15 lessons that follow are designed to teach such estimation strategies as front-end estimation, compatible numbers, clustering, and rounding in lessons with whole numbers, fractions, mixed numbers, decimals, and percents. Each lesson plan includes objectives, teacher background, suggestions for teaching the lesson, acceptable answers for exercises, and six worksheets for student use. (MNS)