Lesson 6-3 Multiply Two Digits by One digit with regrouping

Lesson 6-3 Multiplying 2-Digit by 1-Digit Numbers

How can you multiply a 2-digit number by a 1-Digit number and check the product for reasonableness?

Open Ended

Math Joke:

Why did the two fours skip lunch?

Let's do some warm ups :)

Are you ready ?!

Put the five from 45 in the ones place.

9 x 5 = 45

Put the four from 45 above the 2 as extra tens.

9 x 2 = 18
Add the extra tens.
18 + 4 - 22

Multiple Choice

Which is the best estimate to see if your answer is reasonable for 13 x 7?

• 20 x 7 = 140

• 15 x 7 = 105

• 10 x 7= 70

• 7 x 7 = 49

Multiple Select

Which is the best estimate to see if your answer is reasonable for 24 x 4?

• 20 x 4 = 80

• 20 x 5 = 100

• 30 x 4 = 120

• 40 x 4 = 160

Multiple Choice

Which is the best estimate to see if your answer is reasonable for 33 x 5?

• 30 x 10 = 300

• 35 x 5 = 175

• 30 x 5= 150

• 30 x 6= 180

Multiple Choice

Which is the best estimate to see if your answer is reasonable for 18 x 3?

• 18 x 1 = 18

• 20 x 5= 100

• 20 x 4= 80

• 20 x 3 = 60

Multiple Choice

18 x 3 =

• 243

• 64

• 54

• 21

Multiple Choice

Which is the best estimate to see if your answer is reasonable for 56 x 4?

• 50 x 4 = 200

• 55 x 4= 220

• 60 x 4= 240

• 40 x 4 = 160

Multiple Choice

56 x 4 =

• 224

• 200

• 74

• 284

Multiple Choice

Which is the best estimate to see if your answer is reasonable for 35 x 3?

• 50 x 3 = 150

• 40 x 3= 120

• 30 x 3= 90

• 20 x 3 = 60

Multiple Choice

Ken hosts a radio show 6 times a week.
He hosts the show 49 weeks a year.
Which shows the most reasonable estimate of the number
of times Ken hosts the show in one year?

• 
  5 × 40 = 200

• 
  5 × 50 = 250

• 
  6 × 40 = 240

• 6 × 50 = 300

Poll

I can multiply two digit numbers with and without regrouping and check to see if my answer is reasonable.

What's your level of understanding?

• Level 0

  I'm so confused! It's like you're speaking in Ancient Greek!

• Level 1

  I'm starting to get parts of it but I'm still really confused.

• Level 2

  I get it, as long as I have an example in front of me.

• Level 3

  I get it and I can show my work, but I'm not ready to teach the class yet.

• Level 4

  I get it AND I could teach it! So move over cuz I've got this!