 Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum          A B C  Notes for Session 8, Part A Note 2 We're using the term "ratio" here to represent the comparison of one rational number to another in either a part-to-whole or a part-to-part situation, as you will see in Part A. In mathematical notation, a ratio can be written as a/b or a:b. Proportion is a fractional equation comprising two ratios (a/b = c/d). In common language, "proportion" is often used interchangeably with "ratio." Note 3 The distinction between part-part and part-whole relationships is seldom discussed. Usually we refer to part-part relationships as ratios rather than fractions. The ratio representation is a better way to write the relation, because you won't be tempted to use the rules of fractions to work with them (for example, a ratio of 3 parts to 0 parts cannot be written as a fraction). However, the part-part relationship is sometimes written in fraction form (as it is in this section), even though it represents a ratio. So be sure to understand the difference.    