Reflection: Flexibility Determine Equivalent Ratios - Scale Factor Between Ratios - Section 1: Introduction

The lesson went well for my first class.  Two things helped when showing the example problem.  The first is that we used the value of the ratio (simplest form) to test all of the other ratios.  It can get pretty messy drawing arrows from the value to the other ratios.  I noticed some of my students were just putting a multiplier over the column (ex.  x2, x3, x5 etc...).  I started doing that because it makes the work more clear.

When solving part ii, we put the known value in the table but also modeled the ratio in fraction form.  48/x = 4/3.  We did not cross multiply and divide to solve, we looked for a common scale factor of times 12.

In the Independent Problem Solving Section, I labeled the ratio columns as Batch A, Batch B, Batch C, etc.  This made it easier for students to the three part ratio and made question i more clear.  I could just ask: Which batch is not proportional to the others.

In my second period class today, the fire marshall decided to test our school with a fire drill.  Thank you, Mr or Ms Fire Marshall.  We skipped GP2 on the guided problem solving and did not get to the last Independent Problem Solving problem.  I'll either have to incorporate those problems into tomorrow's lesson or use one of my intervention blocks later in the week.

Helping Students Read Ratios in a Table & FIRE DRILL!!!
Flexibility: Helping Students Read Ratios in a Table & FIRE DRILL!!!

Determine Equivalent Ratios - Scale Factor Between Ratios

Unit 2: Proportional Relationships
Lesson 6 of 12

Big Idea: One useful way to determine equivalent ratios is to find a common scale factor between ratios.

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Standards:
Subject(s):
Math, Number Sense and Operations, tables, proportional relationships
45 minutes

Grant Harris

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