a ratio can have equivalent ratios just like a fraction can have equivalent fractions
DESCRIPTION
If you know the ratio of students to teachers is 5 to 1 and you know there are 15 teachers, is there a way to figure out the number of students?. In this lesson you will learn to solve for missing values in a ratio problem by using multiplicative reasoning. - PowerPoint PPT PresentationTRANSCRIPT
If you know the ratio of students to teachers is 5 to 1 and you know there are 15 teachers, is there a way to figure out
the number of students?
In this lesson you will learn to solve for missing values in a
ratio problem by using multiplicative reasoning
Let’s Review
A ratio can have equivalent ratios just like a fraction can have equivalent
fractions.
2 : 1x3 x3 6 : 3
A Common Mistake
The ratio of students to teachers is 5 to 1. There are 15 teachers.
5
1
wrong row!students
teachers
15
?
Core Lesson
Andy has a ratio of books to DVDS of 3 : 2 in his room. If he has 15 books, how many
DVDs does he have?
How can I use the ratio to help set up
and solve?
Core Lesson Books to DVDs3 to 2
15 books? DVDS
Ratio Actual
3
2
Books
DVDs
15
? How many groups of books does Andy have?
Core Lesson
x 5
x 5
Ratio Actual
3
2
Books
DVDs
15
?? = 10 DVDs
In this lesson you have learned to solve for missing values in a
ratio problem by using multiplicative reasoning.
Guided Practice
Anita collects shells and stones in a ratio of 1 : 2. If she has a total of 6 shells, how many stones does she have?
Extension Activities
Create a flipbook with your own ratio problem and illustrations showing how to solve it using
multiplicative reasoning.
Extension ActivitiesAnnie bakes cookies and cupcakes in a ratio of 2 to 7 for her gift boxes. Her school needs 36 desserts to sell in a bake sale.
How many cupcakes will she bake?
How many cookies will she bake?
Create an illustration and a table to support your work. Explain the multiplicative reasoning used.
Quick Quiz
George buys oranges and apples at a ratio of 2 :5 for his party. If he has 10 oranges, how many apples does he have?Kelly bakes cupcakes and cookies in a ratio of 5 to 3 for her bakery. If on any given day she bakes 15 cookies, how many cupcakes did she bake that day?