Naming Multiplication
Strategies
2.1
Quick Review
 What is a prime number?
 What is a square number?
 What is a factor?
 What is a multiple?
S
Review &
Remember
 What are the prime factors of 36? Use a factor
tree to find them!
36
Guiding Questions
 What are some strategies you can use to
solve multiplication problems?
Objective
 Today, you’re going to discover some different
strategies you can use to multiply 2 digit
numbers. Then, you will make a poster
showing your solution to a multiplication
problem. Let’s remember ways to keep track
of all the parts of a multiplication
problem…Solve this problem, and then
compare solutions with your neighbor:
18 x 14
Discussion
 What was the first thing you did to solve
18x14? I only want your first step.
Different Strategies
 Let’s review some different strategies you can
use to help you solve multiplication problems.
 You will put each one in your journal.
Creating an easier problem by
changing one number
 25 x 36
 25 x 30 =
 25 x 6 =

750
+150
900
Here, we break one number apart to
make it easier to solve.
Breaking 2 Numbers Apart
 35 x 28
 35 x 20 = 700
 30 x 8 = 240
 5 x 8 = + 40

980
Creating an equivalent problem
 35 x 28
 70 x 14 (double 35, halve 28)
 70 x 10 = 700
 70 x 4 = +280
980
Arrays
10
18
18 x 14
14
4
1 way array
Creating A Story
 Can you create a simple story to solve 18x14,
using your strategy?
Drawing a Representation
 Who can give me some ideas on how to
sketch each part of the problem as it is solved
(using 18 x 15)?
35 x 28
You may use any tools you find useful, but none
are required.
Grid
Tiles
Board
300 Chart
 You are now going to make a poster that
includes the following parts:



Create a story problem for 35 x 28
Solve the problem and show your solution clearly
Draw a representation for the problem by using
tiles, an array, or groups
You will use clear and concise notation this year. That
means you will show the steps of your solution so that
they can be easily followed, and reproduced by someone
else. How you solved it, step by step, must be shown!
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 else’s 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.
Guiding Questions
 What are some strategies you can use to
solve multiplication problems?
Independent Work
 Complete the following:
26 x 12
18 x 32
Use any strategy you would like!