Tuesday, February 9, 2016

Comparing (and Eating) Fractions


QUICK REVIEW! When dealing with fractions always remember that the numerator is the number on the top and the denominator is on "de-bottom."

Moving on...

This week, we learned how to compare fractions.  In math, we use universal symbols like 
to compare one number to another.

If you forget which way the symbol faces, just think of the ol' alligator.

He opens his mouth to the larger number. Why?

He LOVES big numbers. He DEVOURS them!


Especially when you're talking about pizza, pie, or Hershey bars.

Who wouldn't want 8/8 of a pizza?

In the problem above, the denominators are the same. This makes comparing the two fractions easy. 

When comparing two fractions with like denominators, the larger fraction is the one with the greater numerator. Let's look at the example above. 8 is greater than 5, sooo...

Now, let's look at some more examples of comparing fractions with unlike denominators.

When you have fractions with unlike denominators like the two above, there are a few ways to figure out which is greater. One method is to find the Lowest Common Denominator (LCD).

First, write down all the multiples of each denominator...

Circle the lowest number that they have in common. This will become the new denominator for both fractions.

As we learned before, when making equivalent fractions you have to X or ÷ the denominator and numerator by the same number. 

Now that the denominators are the same, we can look at the numerator to see which fraction is larger. Which is greater 6 or 5? 6 is larger, soooo...

When I was in 4th grade, I learned another way to compare fractions. I've taught this technique to my students over the years because it's a little quicker than the LCD technique!

5 is less than 12, soooo...

This technique is also known as The Butterfly Method. Can you tell why?

This video will help explain a couple different ways of comparing fractions. Use the method that works for you!

When cross multiplying or finding the LCD, it may help to use a Multiplication Chart. Click the picture below for a cool chart to add to your math notebook!


Fun games, lesson and other resources.

Here is this week's notebook page. Please make sure your math notebook is up to date!

[click on the image for a closer look]

Keep up the great work, kids!


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