2 Digit by 2 Digit Multiplication and Estimation

Multiplication and Estimation

Ms. Hall is challenging you!

We have been crazy busy learning lots of different ways to multiply. Let's review!

Area Model Box

• Distribute large number into place values

• Factors are placed on top of and to the left side of the box

• Multiply across the board for the partial products

• Add all partial products together for the final product

Partial Products

• Break apart factors

• Write out multiplication sentences using Bowtie method

• Solve multiplication sentences to get partial products MAKE SURE to line them up by place value

Standard Algorithm

• Superman or Turtle

• Write the multiplication problem vertically

• Multiply bottom ones by top ones, tens, hundreds from the bottom corner

• Place a zero under that product (turtle egg)

• Multiply the bottom tens digit by the top ones, tens and hundreds.

Multiple Choice

Mr. Cross loves to read and plans to get through his current book in the next 17 days. He did the math and realized he needed to read 64 pages per day to finish in time. How many pages are left in his book?

• 548

• 1,088

• 1,098

• 6,488

Estimation

• Round each factor to the nearest tens

• Rounded numbers are easier to multiply

• Mental multiplication

Multiple Choice

Which shows the best estimate to use to find 43 x 78?

• 40 x 70

• 50 x 70

• 40 x 80

• 50 x 80

Poll

Which method do you prefer?

• Area Model

• Partial Products

• Standard Algorithm

Open Ended

Create one multiplication problem that is a 2 digit by 2 digit. Use the letter x to show a multiplication sign. Do NOT answer it.