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Multiplying 2 digits by 2 digits with area models

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Multiplying 2 digits by 2 digits with area models
Multiplying-2-digit-numbers-with-area-models 256
Description
Exercise Name: Multiplying 2 digits by 2 digits with area models
Math Missions: 4th grade (U.S.) Math Mission, 5th grade (U.S.) Math Mission, Arithmetic essentials Math Mission, Mathematics I Math Mission
Types of Problems: 1

The Multiplying 2 digits by 2 digits with area models exercise appears under the 4th grade (U.S.) Math Mission, 5th grade (U.S.) Math Mission, Arithmetic essentials Math Mission and Mathematics I Math Mission. This exercise uses a visual area model to better understand the concepts of multiplication and place-value.

Types of Problems

There is one type of problem in this exercise:

  1. Multiply the numbers: This problem has a multiplication problem involving 2-digit numbers. The multiplication is performed via the distributive property and the user has to give the solutions to the pairwise products of the digits in addition to the final answer.
    2by2a

    Multiply the numbers

Strategies

This exercise is easy to get accuracy badges because it is still just multiplication in the end. The speed badges are medium because there are several answers that need to be individually filled in.

  1. Multiplying by the number in the calculator first avoids the adding step at the end.
  2. A calculator can be easily used to program something to split this up for the user.
  3. Be careful, the number along the top and the side of the area model is sometimes the first number of the product and sometimes the second. user does have to read carefully.

TI83/83 code

If the number along the vertical axis is inserted first, users can use the following code to yield the five answers to the problem. They can see if they can understand how this works.

Prompt X,Y
int(X/10)->A
int(Y/10)->B
x-10A->C
y-10B->D
Disp 100AB,10AD,10BC,CD,XY

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