This site teaches Arithmetic with Polynomials and Rational Expressions to High Schoolers through a series of 4333 questions and interactive activities aligned to 26 Common Core mathematics skills.
The primary purpose of this problem is to rewrite simple rational expressions in different forms to exhibit different aspects of the expression, in the context of a relevant real-world context (the fuel efficiency of of a car). Indeed, the given form of the combined fuel economy computation is useful for direct calculation, but if asked for an approximation, is not particularly helpful.
This 4-minute video lesson looks at multiplying and dividing rational expressions.
This 5-minute video lesson looks at multiplying and dividing rational expressions.
This 4-minute video lesson looks at multiplying and dividing rational expressions.
Chapter 6: Rational Expressions and Equations
PC20.3 I can expand and demonstrate understanding of rational expressions and equations (up to and including degree 2 numerators and denominators) including:
o equivalent forms of expressions
o operations on expressions
o solving equations that can be simplified to linear or quadratic equations.