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Rectangle Model for 2-Digit Multiplication by Keri Woronka

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This method for multiplication looks complicated; but for students who are visual learners, this is the best way. Everything has a place, and it keeps students organized. It's much harder to just memorize the steps, especially when they don't truly understand the where the numbers are coming from.

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buy a double digit multiplication problem using the rectangular sections using the rectangular sections method you find the partial Sonic and then you add all of those products together to find the final product so let's start with a number sentence let's choose 39 x 54 the first step in solving using rectangular sections is by simply drawing a rectangle the second step is to break up each number apart into place value so the 3 and 39 represents 30  and then you have 9 ones left over so that's the is part of my rectangle  since the area of a rectangle or the space inside of a rectangle is length times width I need to make sure I labeled both the length and the wit so I'm just labeled the width or how wide the rectangle is with the first number 30 + 9 now the Links I need to make sure I label with the second number 54  I need to break up 54 into two numbers using place value and then Plus for more once so I've just broken up 54  into two smaller numbers the next thing I'm going to do is I'm going to multiply the numbers that connect in each box so the 30 in the 50 connectedness first box so I need to multiply three what time is 5030 and 50 in both of those numbers I have two zeros total  someone to write down the two zeros and I'm left with 3 x 5 what is 3 * 5  15 so that's my answer for 50 * 30  now I'm going to look at 50 in the first row and I'm in the second column 50 x 9 in this box right here 15 x 9 is what I know that 50 has 109 does not have so I know I can add one zero and then just multiply the two numbers that I have left 5 and 9 what is 5 * 9 45  I'm next I'm going to go to the second number in the in the second row right here or the number in the second row  and I'm going to multiply that by 30 because this box is are they meet up  so in 30 and 4 I have one zero so all I have left to do is multiply the four times the three four 3 is 12  I have one box left and that is where the 9 in the form meet  what is 9 * poor  36 okay so now the second step to solving a problem using Rec annular sections you can either add all four numbers in the boxes  or are you can break it up and make it a little easier to together  so I can add 1500 + 450 I'll just add across the rose 1500 + 450 is 1900 50  then I'm going to add together the two numbers in the second row 120 + 36 120 + 36  is 156 if you need to write out the algorithm or the equation to add the two numbers to you can do it down here below  play my last step then is to add these two numbers together 0 + 6 5 + 5 is 10 carry the one 9 + 1 is 10 + 1 is 11 1 in 1 + 2 2 4 1 + 1 is 2 my answer is 2106  not a check over my work I'm going to use estimation  I had 39 * 54 I need to round these two numbers and multiply the two rounded numbers to determine whether or not my estimation is close enough to my actual answer 39 I know runs up to in 54 I can either round at 2:55 if I want it really accurate or I can round at 2:50 and I'm going to run it down to 50  0 out of 40 has one zero he has one zero so that's two zeros at the end of my problem and I'm left multiply 5 x 4 which is 20 so my estimate was 2000 in my exact answer was 2106 which is relatively close so I know that my answer is accurate

Uploaded by Lydia McGuire.

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Rectangle Model for 2-Digit Multiplication by Keri Woronka

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