Key fraction vocabulary:
There is a complete website on the basics of fractions at the link below. Before doing anything more on this page, make sure you go to the other webpage and complete all the lessons there first. That page will give you an overview of everything you need to know before coming back here to learn about adding and subtracting fractions.
Click the link to Fun with Fractions!
Click the link to Fun with Fractions!
Adding and subtracting fractions
Now that you've completed the first web page about basic fractions, let's move on to adding and subtracting fractions. The basic concept is the same as adding and subtracting whole numbers. The biggest difference is that now we have two numbers, a numerator and a denominator. What do we do about that?
First of all, we will talk about fractions with like denominators, or denominators that are the same number. If the denominators are the same number, you can just add or subtract the numbers on top and leave the denominator the same. This is because you aren't changing the total number of pieces the object is divided up into, you are adding or subtracting the parts. Let's look at two examples with pictures:
First of all, we will talk about fractions with like denominators, or denominators that are the same number. If the denominators are the same number, you can just add or subtract the numbers on top and leave the denominator the same. This is because you aren't changing the total number of pieces the object is divided up into, you are adding or subtracting the parts. Let's look at two examples with pictures:
So as you can see, we didn't change the denominator in either problem, we simply added or subtracted the top numbers, known as the numerators. The total number of pieces the object was divided up into didn't change, just the selected parts. Below is a video that will help review this concept. Don't worry about what he says about multiplication at the beginning of the video, we will get to that later. Pay close attention to how he shows you adding and subtracting fractions with like denominators.
Getting the hang of it? Like denominators make fraction addition and subtraction super easy. For one more step by step walk-through, check out the Study Jams link below. It will show you a real world example of using fraction subtraction. Don't forget to test yourself when you're done clicking through the step-by-step section!
Study Jams!
Study Jams!
Time to test your adding and subtracting skills! Click the link below to take you to a game that will have you practicing your fraction arithmetic in style. Start with the level 1a. Once that's mastered challenge yourself by trying level 2a. If you are really feeling like an expert, and you have gotten good at equivalent fractions, you can try the 1b and 2b.
Fruit Shoot Fractions
Fruit Shoot Fractions
Multiplying Fractions
Multiplying fractions is easier than adding or subtracting fractions. Why is that? All you do is multiply straight across, meaning you multiply the numerators together and the denominators together. Here is an example:
If you look at the number sentence you can see that we multiplied the numerators across the top: 4 x 2 = 8.
Next we multiplied the denominators across the bottom: 8 x 5 = 40. Our product for 4/8 x 2/5 is 8/40, which is an ok answer. However, there is a better answer! We know that 8 and 40 can both be divided by 8 so there is a lower equivalent fraction. At the bottom you can see that we reduced the fraction of 8/40 to it's lowest form, 1/5. |
Our friend at Math Antics has an excellent explanation of multiplying fractions. Check out his video below to watch step-by-step just how multiplying fractions can be.
Review and activities
By now you should be a fraction genius! If you still have a few questions, that's ok! There is a couple more videos you can watch to help clear things up and then, at the bottom, there are some activities you can work on to practice your fraction skills.
Review adding and subtracting fractions:
Equivalent or reducing fractions:
Ready to challenge yourself? Finding common denominators so you can add and subtract unlike fractions:
Links to activities to practice:
Adding Fractions
Equivalent Fraction Bingo
Adding and subtracting with like denominators
Challenge: Study Jams! Adding and subtracting with UNLIKE denominators
Adding Fractions
Equivalent Fraction Bingo
Adding and subtracting with like denominators
Challenge: Study Jams! Adding and subtracting with UNLIKE denominators