第三单元比例教材分析（Third unit proportion teaching material analysis）.docVIP

第三单元比例教材分析（Third unit proportion teaching material analysis） Third cell ratio First, the teaching content The teaching of number and Algebra in the field of the meaning of proportion, the proportion of properties, solution proportion; also the teaching of space and figure in the field of graphics zoom scale, the significance of solving practical problems, and the relevant scale. The two areas of knowledge combined with teaching, can give practical significance of the proportion of the rich, and can understand the meaning of mathematical graphics zoom, can solve practical problems of scale have more idea and method. The whole unit is arranged with 7 examples and three exercises. It is divided into four sections. Example 1 ~ example 3 and practice nine, graph enlarge and shrink, the meaning of proportion; Example 4 to example 5 and practice ten, the proportion of the nature, the proportion of solution; Example 6, examples 7, practice eleven, the significance of scale and solve practical problems; Practical activities to further experience the enlargement and reduction of graphics. Two, teaching material compiling characteristics and teaching suggestions 1., in the realistic situation and drawing activities, teaching graphics enlarge and reduce meaning. Graphic amplification and reduction is a change in graphics, the object and content of the study is very specific, teaching should be carried out in a realistic situation. Contact the knowledge of fold and ratio to reveal the meaning of graphic magnification. Example 1 First Teaching Graphic amplification, in the rectangular picture amplification situation, asked students to talk about two paintings long relationship, wide relationship. Some students use the double to describe, some students use ratio means, have made use of the existing knowledge, experience. It should be noted that the enlarged painting (second pictures) should be compared with the enlarged picture (the first painting). The textbook sums up the studen