How to Add Fractions with Unlike Denominators Using Models

How to Add Fractions with Unlike Denominators Using Models

Add Fractions with unlike denominator using models.

So this problem we need to find 3/8 + 1/4. So we can fraction models to add 3/8 + ¼. So, our first step is we need to model 3/8 and 1/4.

So, to model 3/8, 3/8 is equal to 1/8 + 1/8 + 1/8. So 3/8 can be model as three equal rectangles, each rectangle representing an eight so it’s three equal rectangles and each rectangle is an eight so this would be 3/8.

Now, let’s model 1/4. 1/4 can be model as a rectangle representing the value of 1/4. So 1/4 would be ¼ so this would be a model for 1/4. So if we want to add 3/8 + 1/4, we’re going to add our model with 3/8 +1/4, okay?

Now because we have different denominators, we have to rename 1/4, okay? So, we’re going to rename the 1/4 to 2/8, all right? So our next step is we need to rename 1/4 as 2/8. So we’re going to take 1/4 * 1.

Now we know that two multiply by four equals eight so we know if we multiply two times four equals eight. So, we multiply the numerator and the denominator of 1/4 by two. So the 1 would be 2/2 because a number over itself is a whole number. So if we multiply our numerator and denominator by two, we can get eight. So we’re going to multiply 1/4 * 2/2, okay?

So, when we do that we get 1*2 is 2 and 4*2 is 8 so, 2/8. So 1/4 is equal to 2/8 so, 2/8 or 1/4. So now 1/4 can be written as 2/8, alright? So do you see that how they’re equal?

So now, our last step after we renamed is now we can add3/8 and 2/8. Okay? So if we go back to our models, we have 3/8 and now we’re going to add our 2/8.So now, we’re adding our 2/8.And when we do that, we get a total of 5/8 so 3/8 + 2/8 equals 5/8, all right? So, if we go back to our problem, 3/8 + 1/4 is 5/8.

Okay, things to remember and to keep in mind are that we can use fraction models to add two fractions so when we have two fractions, we can use fraction models.

To add fractions with unlike denominators, first, we need to rename the fractions with like denominators. For example, when adding 3/8 and 1/4, 1/4 can be written as 2/8 and then we can go on with our addition.


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