Naming Multiplication Strategies 2.2

1
Naming Multiplication Strategies2.2
2
Warm Up

• This number is less than 50
• This number is not a factor of 100
• This number of tiles will make only one
  rectangle.
• Work with your partner to come up with possible
  answers.

3
Naming Strategies

• Now we are going to explain our solutions. As we
  look at each poster, try to name the strategy
  after seeing the first step.
• If you are explaining a strategy, your job is to
  help us follow your steps and to use your story
  or picture to explain how you are keeping track
  of the parts.
• If you are listening to someone elses strategy,
  your job is to listen carefully, try to
  understand the strategy being explained, and
  compare it with your own strategy. Ask questions
  if you need a clearer explanation.

4
Lets review our posters 35 x 28

• Which of these representations were the same?
• Which are different?
• Are there any representations that seem
  particularly clear to you?
• Are there ways we can use shortcuts in our
  representations?

5
Guiding Questions

• What are some strategies you can use to solve
  multiplication problems?

6
Jason received 10.00 each time he took out the
trash. He took the trash out twice a week. After
5 months, how much money would Jason have?

1. 50.00
2. 500.00
3. 400.00
4. 100.00

7
The maintenance crew is responsible for cleaning
208 windows. Each window has 15 panes of glass.
How many panes does the crew have to clean?

1. 3,210
2. 3,120
3. 3,010
4. 2,920

8
Which of these is not a factor of 80?

1. 8
2. 3
3. 10
4. 20

9
Objective

• Today, youre going to practice using different
  multiplication strategies to solve 2 digit
  problems. We will work on 2 different kinds of
  arrays!
• Guiding Question What are some strategies I can
  use to solve multiplication problems?

10
Arrays
35 x 28
28
Lets think about teams. Its field day, and all
the teams need to line up in the field to make a
huge rectangle. There are 35 teams with 28
students on each team. The problem is to figure
out how many students there are on all of the
teams. So if we start with 35 x 20, who can
explain what 35 times 20 means in terms of the
teams? What part of the problem have we solved?
What else do we need to do?

• 20 8
• 35

35 x 20 700
1 way array
11
2 way Array
35 x 28
28

• 20 8
• 30

30 x 20 600
35
30 x 8 240
5
5 x 8 40
5 x 20 100
12
U.S. Algorithm

• 29 x 16

13
Lets Practice!

• Allie had 38 orders for bouquets. Each bouquet
  uses 19 flowers. What is the total number of
  flowers needed to fill the order.

14
Justin Book Fair

• There are 27 book fair shelves in the Library.
  Each shelf has 54 books on it. How many books
  are in the book fair?

15
Challenge!

• There were 48 teachers present at the staff
  meeting yesterday after school. The meeting was
  held in the Art room. There were 8 tables
  available in the Art room. How many teachers were
  seated at each table?

16
Problems Involving Teams

• There are 37 teams and 28 students on each team.
  How many students are there?
• There are 68 teams at the tournament. Each team
  has 16 players. How many players are at the
  tournament?
• There are 49 teams in the football league. Each
  team has 28 players. How many players are there?
• There are 57 teams entered in the relay race on
  Field Day. Each team has 32 people. How many
  people are entered in the relay race?
• There are 44 teams and 35 people on each team.
  How many people are on the teams altogether?

17
Independent Assignment

• Select THREE of the five problems below and solve
  using any strategy you choose. Show your work,
  using CLEAR and CONCISE notation.
• 27 x 19 42 x 32 76 x 8 82 x 56 65 x 14

18
Guiding Questions

• What are some strategies you can use to solve
  multiplication problems?