The science-math strand of unit six for second graders deals primarily with the concepts of conservation, relativity, adaptation and ecology. This teacher's guide to Kits 21-24 presents instructional and assessment activities revolving around the basic theme of the neighborhood as a community. Focus, objective, and materials for each activity are given in English and Spanish, with teacher instructions in Spanish only. Math activities review place value and the associative and commutative principles of addition and subtraction. Students measure line segments and are introduced to points, parallel lines, and intersections. One, two, and three digit numbers are added and subtracted, and their place values discussed. Through discussion, simple experiments, and observation, students learn matter, the forms it can take, and how matter and energy exist in fixed but interchangeable quantities. Relativity is understood as pupils describe the position of objects relative to other reference objects or to themselves. Reproductive patterns are observed in some plants and animals; adaptation is introduced with study of how organisms depend on and adapt to environment. The ecology section deals with the interaction of plants and animals with their environments and their dependence upon each other. (DS)