Lesson video

Hi, I'm Mr Chan, and in this lesson, we're going to learn about equivalent fractions.

In order to understand equivalent fractions, it's really good to have a look at bar models.

So here we have a whole split up into five to create fifths, and we also have the same sized whole, split up into 10 to create 10ths.

So in our first example, if I think about one fifth, I would shade in one part of that whole to create one fifth, and to create an equivalent amount in the tenths fraction bar model, I would have to shade in two.

So this is why we can understand that one fifth is equivalent to two 10ths.

Let's have a look at another example.

Let's look at three fifths.

So I've shaded in three parts of that whole.

So, in order to shade in an equivalent amount in tenths fraction bar model, we would have to shade in six.

So in this example we can say that three fifths is equivalent to six tenths.

So here's a question for you to try.

Pause the video to complete the task, resume the video once you're finished.

Here are the answers for the first question.

You'll notice that for each part the equivalent fraction models have been drawn to be the same size.

So in part A, we can see that one half is equivalent to three sixths.

Part B, six ninths is equivalent to two thirds.

And in part C, two fifths is equivalent to eight 20ths.

So fraction bar models are a great way of finding equivalent fractions, but we don't always want to be drawing fraction bar models to find them, let's look at a more efficient way.

So if we look at what's happening with the numerator and denominators for these equivalent fractions, when we say three fifths is equivalent to six tenths, we notice that the numerator is getting multiplied by two, and the denominator is getting multiplied by two.

So three multiplied by two gets to six, five multiplied by two gets us 10.

Let's look at another example.

We have another equivalent fraction here, three fifths equaling nine 15ths.

Now, again, when we look at what's happening with the numerator and denominator numbers, we can see that they're getting multiplied by the same amount.

Another example.

Three fifths is equivalent to 12 20ths, we can see that using the fraction model, and again, we can notice that the numerator is getting multiplied by four, as is the denominator.

So one method to find equivalent fractions is by multiplying the numerator and denominator by the same amount.

Here's some questions for you to try.

Pause the video to complete your task, resume the video once you're finished.

Here are the answers.

So in this question, we've got to calculate the missing numbers for each of the equivalent fractions.

So we need to figure out what we multiply either the numerator by or the denominator by in order to figure out the missing number.

So if we use question A as an example, we figure out that what we multiply four by to get to 12, well four multiplied by three gets me to 12, so if I do that for the numerator, one multiplied by three, we'll get to three.

Part D is a little bit more different than the other questions, however because these are equivalent fractions, we can think of the fraction with the missing number first.

That's equivalent to six ninths.

Thinking about that question in that order will help you with that question.

Hopefully you got that correct.

Here's another question for you to try.

Pause the video to complete your task, resume the video once you're finished.

Here are the answers.

In this question, we've got to figure out which cards are equivalent to six 20ths.

We see that there are five cards that are equivalent, so it might be better to look at why one third isn't the equivalent to six 20ths, and focus on that.

So, when we're comparing one third and six 20ths, well I could look at the numerator, one multiplied by six, would get me to six on the numerator, so let's try that with the denominator, three multiplied by six, would get me to 18, and we can see that 18 isn't the denominator for six 20ths.

Here's some questions for you to try.

Pause the video to complete the task, resume the video once you're finished.

Here are the answers.

In this question we're told all the fraction cards are equivalent, so we've got to figure out the values of A, B and C.

Intuitively, we try and work out the value of A first, however, that's probably a little bit more difficult than working out the value of C first, because we can see that the denominator 15 becomes 30 as an equivalent fraction, and that denominator is simply getting multiplied by two.

So we can figure out the value of C by multiplying the numerator 10 by two to give us an answer C equals 20.

Hopefully that's the way you started this question.

That's all for this lesson.

Thanks for watching.