RCN Lesson 20: Standard Algorithm: Multi-digit Numbers without Composing - EDWIN TORRES-BATISTA | Library

Develop Understanding
Today's Learning Goal: (G5, U4, L5)
Use the standard algorithm to multiply up to three-digit numbers and two-digit numbers, without composing new units.
Today's Materials:
Laptop
Laptop charger
Pen/Pencil/Paper (optional)
Please complete the Jump Start (activator). You have 5 minutes before we review. This is independent it should be silent.
Reminders:
1. Ready for class
2. No cellphones
3. Volume must be low.
4. Read and follow all directions
5.) Take your bag off and immediately begin the Activator.

JUMP START: Partial Products
(5 MIN)
Find the value of each product mentally.

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20 x 3

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24 x 3

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120 x 3

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140 x 3

Lanuch - (10 min) 
I'll model question 2
We'll Try question 3 
You Try question 4   

ACTIVITY 1: Compare Two Algorthims - (15 min)  

Two algorithms for finding the value of 413 x 21 are shown below:

Algorthim 1:

Algorthim 2: 

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How are the two algorithms the same? How are they different?

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Explain or show where you see each step from the first algorithm in the second algorithm.

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How do the final steps in the two algorithms compare?

ACTIVITY 2: Use the Standard Algorithm - (15 min)

Use the standard algorithm to find the value of each expression.

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202 x 12

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122 x 33

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321 x 24

Diego found the value of  301 x 24 Here is his work. 

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Why doesn’t Diego’s answer make sense?

LESSON SYNTHESIS - (5 MIN)

Find the value of 322 x 41 using the standard algorthim. 

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322 x 41

COOL DOWN - Standard Algorithm without Composition of a New Unit 

Use the standard algorithm to find the value below: (SHOW YOUR WORK)

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4

203 x 23

Closure Questions:
The steps from Activity 1 are called what?
Name the components in the equation:
10 x 12 = 120
What is the algorithm we used today to multiply two two-digit numbers