Distributive Property and Problem Solving Using Units of

2-5 and 10

Module 1: Lesson 20

Solve 2 step word problems involving multiplication and division and assess the reasonableness of

answers

Fluency PracticeSkip Count by Fives

(12 minutes)

Ready, Set, Go! Let’s do Sprint A, Skip count by 5’s!

Count by 3’s forward and backwards!

Ready, Set, Go! Now let’s do Sprint B, Skip count by 5’s!

Application Problem(8 minutes)

Red, orange, and blue scarves are on sale for $4 each. Nina buys 2 scarves of each color. How much does she spend? Use the RDW process using a tape diagram to

model the problem.

Application Problem.(8 minutes)

Concept Development(30 minutes)

Personal white boards*

Problem 1: Model a two-step problem with a tape diagram

Compare this problem to the one that you just solved. What is different?

Red, orange, and blue scarves are on sale for $4 each. Nina buys 2 scarves of each color. She also

buys a hat that costs $4. How much does she spend altogether? This tape diagram shows the

application problem. Let’s call one of these boxes a unit.What does 1 unit represent? How much is 1 unit? What do 6 units represent?

What equation did you use to find the total cost of the scarves?

Concept Development(30 minutes)

I have added a new unit, label, and question

mark to represent our new problem.

How many units did we add

together to find the total of both of

these units?

What multiplication sentence can we use to find the cost of

the hat and scarves?

Concept Development (30 minutes)

Problem 2Mr. Lim buys 7 plants for his garden. Each plant costs $5. The next day he buys a rose bush that also costs $5. How much more do the 7 plants cost

than the rose bush?

What information is the unknown?

Notice there are 2 unknowns. Let’s first draw and label a tape diagram to model where the unknown is the

cost of the 5 plantsWhat equation can we

use to find the cost of the 5 plants?

Concept Development(30 minutes)

Now let’s answer the question. How much more do the 5 plants cost than the rose bush?

Write an equation and solve the problem on your

personal white boards.

Concept Development (30 minutes)

• Is $30 a reasonable answer? Why or why not?

Tell your partner how this diagram represents the problem

on its own.

Given what you know, is it necessary to find the total cost of the plants? Why or

why not?

Explain to your partner the difference between the 2

ways of solving this problem.

Concept Development (30 minutes)

Problem 3- Model and solve a the two step problem.

10 children equally share 40 almonds. How many almonds will 3 children get?

Model and solve the problem. Make sure you reread the

problem to make sure that you have answered the question. Then think about whether or not the answer makes sense.

This is how we check the reasonableness of answers.

Problem Set (10 minutes)You have 10 minutes to complete the problem set pages.

Debrief (10 minutes)Let’s review your solutions for the problem set.

Exit Ticket(3 minutes)

This is where you are going to showus that you understand what we learned today!

We will learn if you are ready for the next lesson!

Homework

3-20 Homework Worksheet

Is Due Tomorrow!