How To Understanding Calculating Percentages
How To Calculate Percentages: A very easy method for determining the percentage of a number. Includes an explanation of how to determine one percent of any given number and then multiply that value by the desired percentage.
Hi, my name is Charles and I'm one of the math teachers from the maxim workshop. I'm just going to now teach you how to do some math. I'm going to show you how to calculate percentages.
Now, percentages relate to finding one part in a hundred of anything. So if you were to imagine the price of a jacket at a shop and you were to take that price and divide it into a hundred parts, one of those parts would be a percentage. And that's the basis of what we're going to be doing here.
We're going to be trying to find one percent and then multiply it by however many percents we want. So, if we had a jacket and it was twenty pounds, and we wanted to work out, say, fifty percent of this, what we would first off do is take this twenty percent and say we want to find one percent, okay? Now this is a technique that you can do with any question, so, this is why I don't just say it's half of this value. What you would do is you would find that one percent and then go and multiply it by fifty.
So in order to find one percent of this, remember, this relates to a hundred parts. It's the original price. So to find one percent, we would first of all divide this by a hundred.
Okay? So, what this gives us now is a decimal jump of two to the left, so, one, two. Okay? So, zero point two pounds, okay? I'll put that twenty in just to show you how many places it jumped. So, again, if you look at this we jumped twice.
Now this box relates to one percent, okay? Now, if you think about one percent, we're trying to find fifty percent of this, because it might be a sale price or something like that. So it's common to see in shops where you have a jacket fifty percent off so would even need to be able to calculate what that is yourself. So, the next thing to do is say, to take one percent of fifty percent is just a multiplication of fifty, okay? So that will give you fifty percent.
So you do that with the price as well, you multiply this by fifty. So, we've got zero point two zero times fifty. Now the easiest way to do this again is just to take this fifty and say you have, instead of fifty, you've got five times ten.
Okay? So, multiply this ten by this zero point twenty first, and then multiply the five. So if you multiply this ten by this zero point twenty, you move the decimal point back. So you have this.
And then you have zero point two, and it jumps over so we've got just two now, times five. Now, if you multiplied the five by whatever you've multiplied here and here which is two times five, then you will have five times two which is just ten, and that gives you ten pounds, okay? So, obviously a half, fifty percent relates to a half, and a half of twenty will give you ten pounds, but this technique, again, you will always look for one percent first, and then multiply whatever number you have as the one percent value. You multiply that by the percentage that you're looking for, okay? I'll give you just one more example using different values.
So imagine if we have twenty-four pounds, and we're trying to look for sixty-two percent. Again, we would look for one percent of this, and then multiply that one percent by sixty-two. So, dividing through by a hundred gives us one percent, okay? That will give us zero point two four.
So those two zero's gives us two jumps which is zero point two four. Now this relates to one percent, okay? Now, straight off of that, we want to look at the percentage that we're looking for and it's sixty-two percent. So we want to multiply this by sixty-two, okay? So, we have zero point two four times sixty two.
What we're going to do is we're going to shift these, I mean this decimal point back two places, and then we're going to multiply whatever we have, which would be twenty-four times sixty-two, and then in the answer we're going to shift the decimal point forward two spaces just to preserve the fact that we're multiplying zero point two fo