Simplifying Logarithms

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Students will be able to define and simplify logarithms.

Big Idea

It's just an exponent, it's just an exponent, it's just an exponent...

Warm Up and Homework Review

10 minutes

I include Warm ups with a Rubric as part of my daily routine. My goal is to allow students to work on Math Practice 3 each day. Grouping students into homogeneous pairs provides an opportunity for appropriately differentiated math conversations. The Video Narrative explains this lesson’s Warm up-Simplifying Logarithms which asks students to compare two exponential equations.

I also use this time to correct and record the previous day's Homework.  

The History of Logarithms

30 minutes

This lesson begins with a history lesson through a short YouTube video. 

 Logarithms are more meaningful when they are viewed in their proper place in history.  There are links to both the video and some addition historical information in the PowerPoint and at the end of this lesson plan.  

Introduction to Logarithms

40 minutes

The next step is to create a sense of how logarithms are constructed (Math Practice 2).  I have found it is extremely important to focus on the fact that the answer to a logarithm is the exponent.  This takes them from being a mysterious unknown into something the students can feel comfortable with.  

Detailed presentation notes are included in the PowerPoint.

Guided Practice

30 minutes

The remainder of the lesson consists of Guided Practice.  We now practice converting logarithms to exponents and vice versa.  The final part of this lesson has students simplifying basic logarithms without a calculator.  Some of these may be tricky to the students.  I remind them that they can transform them from exponential to logarithmic form and vice versa.


1 minutes

The Homework reinforces the skills from the lessons, extends into slightly harder problems, and then does a single problem preview of the next day's lesson. 

Exit Ticket

5 minutes

I use an exit ticket each day as a quick formative assessment to judge the success of the lesson.  

This Exit Ticket is checking that students know what a logarithm is asking as well as how to simplify it.