Video: GCSE Mathematics Foundation Tier Pack 4 • Paper 2 • Question 2

GCSE Mathematics Foundation Tier Pack 4 • Paper 2 • Question 2

02:49

Video Transcript

Write three-quarters as a percentage.

Now, there’s a couple of ways we can actually go about answering this question. First of all, we’re gonna look at it coming from a decimal. Then, we’ll have a look at how we can do it with the actual fraction itself. So one of the relationships you should know is that a quarter is equal to 0.25.

So therefore, three-quarters is gonna be found by multiplying three by 0.25 because if one-quarter is 0.25, then we find three-quarters by multiplying three by 0.25. So therefore, this is gonna give us 0.75.

But however, if you do actually forget the relationships, you do forget that a quarter is 0.25, you can actually work it out because three-quarters means three divided by four. And we can do that using the bus stop method.

So we can do fours into three. Well, it doesn’t go. So you carry forward the remainder of three. So you put a decimal and a zero and we carry forward the remainder of three. So then, we can see fours into 30. Well, this goes seven times with a remainder of two. So then fours into 20 go five times with no remainder. So we get 0.75.

But we haven’t actually finished here because we got 0.75. But this is actually a decimal. We haven’t actually got the percentage we want yet. So what do we do next? Well, to change 0.75 into a percent, what we do is actually multiply 0.75 by 100. So this is gonna give us 75 percent. And that’s because if you multiply 0.75 by 100, you move each of the digits up two place values to the left. So it gives us 75 percent.

Okay, great, so we know that three-quarters is equal to 75 percent. That’s the first method. Now, we’ll have a look at another method. Well, for this alternative method, what we do is we actually think about percent being out of 100. So that’s what it means; it means out of 100.

So therefore, if we’ve got three-quarters, what we want to turn this into is a fraction, where 100 is our denominator. So in order to actually convert three-quarters into an equivalent fraction with 100 as the denominator, we have to see what we need to multiply the denominator, so four by to get to 100. Well, we need to multiply it by 25. So therefore, we’re gonna have to do the same to the numerator. So we’re gonna multiply three by 25.

Well, three multiplied by 25 is 75. So then, we get 75 over 100. So therefore, we can say that three-quarters is gonna be equal to 75 percent and that’s because 75 over 100, percent means out of 100, so it means it’s gonna be 75 percent.

Just a quick note, the three dots I’ve drawn there — they look a little bit like a triangle — that actually means therefore.

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