Videos and lessons to help Grade 4 students learn to multiply or divide to solve word problems involving multiplicative comparison, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem, distinguishing multiplicative comparison from additive comparison.

Common Core: 4.OA.2

- I can explain the difference between multiplicative (as many times as) and additive (more) comparisons.
- I can determine when to multiply or divide in word problems.

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More Lessons for Grade 4

Common Core for Grade 4

Additive Comparison: Darlene has 7 apples. Juan has 4 more. How many does Juan have?

Multiplicative Comparison: Darlene has 7 apples. Juan has 4 times as many. How many does Juan have?

Solving Word Problems with multiplication comparisons

Example: John has three times as many apples as Sally. How many apples does John have?

This lesson shows how to use models for comparison problems, using addition, subtraction, multiplication, and division.

Using bar models to solve a word problem that involves "three times as many" and "4 more".

Example:

Claire loves animals. She has 3 times as many goldfish as she has chickens. She has 4 more hamsters than chickens. Altogether, she has 49 animals (goldfish, chickens, and hamsters). How many more goldfish does she have than hamsters?

In this lesson you will learn to solve comparison (measurement) multiplication and division problems by drawing a diagram.

Example:

1) Dan went to the market on Friday. He bought two tomatoes. On Sunday, he bought 6 times as many. How many tomatoes did he buy on Sunday?

2) In July, a construction company built 360 miles of road. In February, the company laid down 60 miles of road. How many times more road did the company complete in July?

Example:

Cheryl purchased five books for the same amount as Carla, who purchase 3 of the same books and a $8 briefcase. What was the cost of each book?

Example:

Kyle is making 9 birdhouses. He uses 8 nails for each birdhouae. If Kyle has a box of 100 nails, how many nails will he have left after he makes the birdhouses?

Ms. Upton spends a total of $42 for 3 sweaters for her children. Each sweater costs the same amount. How mch does each sweater cost?

How to use models, illustrations and writing to solve multiplicative comparison questions?

Example:

1) Darlene picked 7 apples. Juan picked 4 times as many as Darlene. How many apples did Juan pick?

2) Joelle read 9 books in the fall. George read 7 times as many books. How many books did George read?

3) Sarah is 12 years old. George is g years old. Sarah is 3 times as old as George. How old is George?

Examples:

1) Suzie is 4 feet tall. There is a tree in her yard that is 9 times taller than she is. How tall is the tree in Suzie's yard?

2) The tree in Suzie's yard is 36 feet tall. The tree is 9 times as tall as Suzie. How tall is Suzie?

3) Suzie is 4 feet tall. The tree in her yard is 36 feet tall. How much taller is the tree than Suzie?

Write an equation and solve

Mrs. K is five times as old as her son. If she is 35, how old is her son?

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