Transcript 13 x 8 = 104

Warm Up
1. 106 x 4 =
3. The table below shows the average number of
students in each class at Granger.
Number of
Classes
Number of
Students
2
42
4
84
7
147
9
How many students are in 9 classes?
2. 238 ÷ 7 =
4. 30,981-26,705
For his birthday, Nicholas received $20.00
and 29 toy cars. The week after his
birthday he rode his bike 1.7 miles to the
mall to go shopping. He purchased a book
for $4.25, two puzzles for $1.25 each, and a
model airplane for $5. All the models in
the store cost $5.
5. If Nicholas places 7 toy cars in each box,
how many boxes will he need to store all
of the toy cars he received for his
birthday?
Multiplication Clusters
Multiplication Clusters are a set of problems that are related in some way to the
final problem. Although they are not all related to one another. They are all
related to the final problem.
13 x 2 =
13 x 4 =
3x8=
12 x 8 =
Final Problem: 13 x 8 =
For example, 12 x 8 is not closely related to 13 x 4, but it is related in a
different way to 13 x 8, the final product you are trying to solve in this cluster.
Work with your shoulder partner to solve the Multiplication Cluster. Solve the
first four problems first and chose one or more problems in the cluster to
help you solve the final problem,
Discussion: Multiplication Clusters
13 x 2 =
What strategies did you use to solve the
final problem? (Record some strategies
on Chart Paper to be used later)
13 x 4 =
3x8=
12 x 8 =
Final Problem: 13 x 8 =
Possible Strategy #2
3 x 8 = 24
10 x 8 = 80
13 x 8 = 104
Q: What is happening in this strategy?
A: 13 is broken apart by place value.
Students use 3 x 8 from the cluster and
then add 10 x 8, which is not in the
cluster.
Possible Strategy #1
13 x 2 =26
13 x 4 = 52
13 x 8 = 104
Q: What is happening in this strategy?
A: One of the factors is doubled each time,
which doubles the product.
Possible Strategy #3
12 x 8 = 96
96 + 8 = 104
13 x 8 = 104
Q: What is happening in this strategy?
A: Some of you may just know that
12x8=96. So you can just add 8 more to
solve for 13x8.
Independent Work: Multiplication Cluster Problems
Complete Student Activity Pages 57 and 58 (Give students
about 25 mins)
In the space beside each set of cluster problems you solve,
explain which set of cluster problems you used to solve for
the final product and explain how you used them.
Once your paper is complete: Play Multiplication Migration
in groups no larger than 4.
Discussion: Representing Cluster Problems with Arrays
Let’s look back at the strategies you used to solve 13 x 8. How can we
use arrays to show how you used the problems in the cluster?
13
8
I am going to start by drawing just the finaly problem 13 x 8. We will imagine all
the squares are there that make up the array.
How many rows are in this array?
How many squares are in each row?
Discussion: Representing Cluster Problems with Arrays
10
8
13
10 x 8
3
3x8
Possible
Strategy #2
3 x 8 = 24
10 x 8 = 80
13 x 8 = 104
For example, let’s use possible strategy #2.
How should I break up this array to match Possible Strategy #2?
Now that you have seen an example, draw areas to match the strategies you
used to solve for the final problem.