**http://illuminations.nctm.org/LessonDetail.aspx?id=L817**

### COMMON CORE STANDARDS

**Content Standards**

F-IF.C.8 Write a function defined by an expression in different but equivalent forms to reveal and explain different properties of the function.

F-BF.B.5 (+) Understand the inverse relationship between exponents and logarithms and use this relationship to solve problems involving logarithms and exponents.

**Standards for Mathematical Practice**

MP.2 Reason abstractly and quantitatively.

MP.3 Construct viable arguments and critique the reasoning of others.

MP.5 Use appropriate tools strategically.

MP.6 Attend to precision.

MP.7 Look for and make use of structure**.**

### DESCRIPTION OF LESSON

This lesson “Algebra 2 – Logarithms Demystified” from NCTM.org focuses on developing the rules for logarithms in Algebra 2. The lesson follows ones that develop understanding of what a logarithm is and how it is used. In this lesson, students make and use logarithm slide rules to discover the properties of logarithms. Students will use a simplified slide rule to add and subtract visually, compare logarithms for different orders of magnitude, and to discover the properties of logarithms.

### CAUTIONS

Connecticut teachers should be aware that they would need to include supports for students working above/below grade level, those students who are identified as students with disabilities and for English language learners (ELLs). Teachers should make connections to other domains that include exponents and properties of exponents. The lesson does not include a pre-assessment or self-assessment. The assessment does not provide rubrics or student work samples.

### RATIONALE FOR SELECTION

- Most of the instructional materials necessary are provided.
- The lesson contains explicit details on suggested instructional approaches and overviews.
- The task is rigorous and encourages contextual understanding of the standards. It is relevant, and thought-provoking.