Opening Activity Count up the number of items

Opening Activity Count up the number of items in each example below. Write these on your index cards. Flutes: Drums: Milk Cartons: Sandwiches:

INTRODUCTION TO RATIOS

Table of Contents Date 8/26 Lesson Place Value and Rounding 8/26 Order of Operations 8/26 Decimal Operations 8/28 Fraction Operations 8/31 Mixed Numbers and Improper Fractions 9/2 Introduction to Ratios Page # Unit 3 1

Learning Goal LG 701: Students will be able to analyze proportional relationships and use them to solve real-world and mathematical problems.

What are we doing today? Today I am learning about ratios. So that I can accurately read and write ratios in various forms. I’ll know I’ve got it when I can determine the ratio of basketballs to footballs in the problem below.

A little humor to start us off… Poor Horatio

Ratios in real life Bing vs. Google

What is a ratio? • A ratio is a comparison of two quantities. • A ratio means that for every ______, there is (are) ______. • Example: For every 2 red paper clips, there are 6 blue paper clips. The ratio of red paper clips to blue paper clips can be written in three ways…

Writing Ratios For every 5 dogs, there are 3 cats. Write this ratio three different ways. For every 7 popcorn buckets, there are 4 sodas. Write this ratio three different ways.

Simplifying Ratios • Ratios are simplified the same way that fractions are simplified. • Whatever we do to one number, you must do to the other. • The ratio of red paper clips to blue paper clips was 2 : 6. What is this ratio in simplest form?

Does Order Matter? When writing or reading a ratio, does the order matter? For example, is 10 to 1 the same thing as 1 to 10? Order does matter when writing or reading a ratio. Changing the order changes the meaning of the ratio. For example, on a school field trip, the ratio of students to chaperones must be 10 : 1. For every 10 students, there must be one chaperone. If we change the order, we are saying for every 10 chaperones, there must be one child.

Which is correct? What is the ratio of moons to stars? 10 : 5 or 5 : 10

Which is correct? What is the ratio of triangles to total shapes? 14 : 8 or 8 : 14

Ratios in our classroom Let’s find out some ratios within our classroom. Stand up and head to the side of the room that applies to you. Boys Girls Cats Dogs Chocolate Vanilla Salty Sweet

Let’s Practice Write the ratio of one item to the other. Simplify if possible. 6: 8 or 3: 4 3 to 9 or 1 to 3

More Practice

Ratios

Exit Slip Go back to your index card from the opening activity and write the following ratios in simplest form: • Drums to all instruments • Milk cartons to sandwiches