 # 4th Grade Math Multiplying 2-digit by 2-digit Numbers Using the Area Model / Box Method.

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4th Grade Math Multiplying 2-digit by 2-digit Numbers Using the Area Model / Box Method

Slide 1 Here's the Problem Let's go with 23 x 45

Slide 3 Expanded Form 23 becomes 20 + 3 45 becomes 40 + 5

page 4 Drawing Time! Draw a window with 4 panels. 20 and 3 go on the top 40 and 5 go on the side

Okay, Let's Multiply! ❖ The top left square... ❖ Is under the 20... ❖ And beside the 40... ❖ So multiply 20 x 40 ❖ 800 in the 1st square

Square 2 ❖ The top right square... ❖ Is under the 3... ❖ And beside the 40 ❖ Multiply 3 x 40 ❖ 120

Down on the Corner ❖ Bottom left square... ❖ Under the 20... ❖ Beside the 5 ❖ 5 x 20 ❖ 100

The Last Panel ❖ The bottom right square... ❖ Is under the 3... ❖ And beside the 5 ❖ 3 x 5 ❖ 15

How much are those numbers in the Window? ❖ These 4 numbers are the partial products ❖ Add them together to get the final answer ❖ Thanks to the commutative property the order that you add them doesn't matter ❖ In this example, we are adding across first, then adding our two answers

Add it up! ❖ Adding the top row ❖ 800 + 120 ❖ 920

Bottoms Up! ❖ Adding the bottom Row ❖ 100 + 15 ❖ 115

Summing it Up ❖ Add the two sums together ❖ 920 + 115 ❖ 1,035

Almost the last page This is it! 23 x 45 = 1,035

This is the last page I hope this helps The end (Told you it was the last page)

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