This unit is intended to teach estimation skills in such a way as to be relevant and useful to students as they apply them in various problem-solving activities. The teaching activities feature the earth, exploration into space, and the other worlds in the solar system. The teacher's guide contains four modules. Module I suggests the use of several multi-media experiences to set the stage for the activities that follow. Module II, "The Solar System," incorporates teaching activities dealing with rounding numbers, estimation of sums, differences, products and quotients, graphing, and the application of these skills in problem solving. Module III, "The Space Shuttle," addresses the use of the space shuttle and stresses the mathematical concepts of ratio and proportion. Module IV,"The Space Colony," uses geometric concepts as students build a three-dimensional living space colony. The entire unit includes teacher notes, student worksheets, answer sheets, activity cards, transparency masters, and classroom games. It also contains a "Math Space Mission Fact Book," an annotated bibliography, and a "Math/Space Mission Problem Deck" (of card) for students. A "Solar System Planet Card Deck" is not included here insofar as it is duplicated in the "Math Space Mission Fact Book". (TW)