## Reflection: Flexibility Finding an Original Value - Section 1: Introduction

When I planned this lesson, I made the assumption that students would be comfortable with the various methods for finding sale prices and total with tax.  For example, if an item is on sale with a 30% discount then the sale price is 70% of the original price; or, if an item has 8% tax the total price with tax is 108% of the original price.

In reality, the majority of my students were not yet comfortable with this AT ALL.  I try to make lessons that are focused on a specific outcome.  Without students having the mastery of the mentioned concepts, this lesson become too difficult.  Students were struggling to grapple with these "prerequisite" concepts and consequently started to lose the main point of the lesson- we can take a percent and scale it down to 1% and then scale this value up to 100% to find the original amount.  I ended having to give the values without expecting students to find it.

Eyes Bigger Than My Stomach
Flexibility: Eyes Bigger Than My Stomach

# Finding an Original Value

Unit 5: Percent and Proportional Relationships
Lesson 9 of 15

## Big Idea: Scale a given value down to 1% and then multiply by 100 to find the original value.

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2 teachers like this lesson
Standards:
Subject(s):
Math, Number Sense and Operations, Percentages, finding the whole, finding original, scaling percents
45 minutes

### Grant Harris

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