Can somebody teach me how to do porcentage the easy way?

Question

I work in sales and my boss wants to do porcentage without calculator. tell me how please

Answer 1

its percentage end the easy way to do it is:

is   %              

_ = ___

of   100

Answer 2

Mental Math: Percents

August 29, 2006

Can you find ten percent of a number? Can you add? If so, I can show you a faster way to calculate percents.

With the possible exception of 50%, there's no percentage easier to calculate than 10. Just move the decimal place one to the left. 100 becomes 10, 55 becomes 5.5, and 0.8 becomes 0.08.

Of course, the GMAT usually doesn't ask you to come up with ten percent of things. However, ten percent (and, by extension, one percent) is the fundamental building block of all other percents. Let's start with a couple of simple examples.

Tipping

The classic example of mentally calculating percents is tipping. Many people use the

"double the tax" method, which works nicely in states where the sales tax is near eight percent. When you compute a tip this way, here's the mathematical representation of what you're doing, where x stands for the total price of the meal:

16% * x = 2 * 8% * x

If you want to be more generous and tip 20%, you can use the same reasoning, just starting with 10% instead of 8%:

20% * x = 2 * 10% * x

In your head, you're calculating as follows: "The tab is $65, so ten percent of that is $6.50, which means my tip should be double that, which is $13.00." Percents, of course, can be more complicated than that, but that technique is the backbone of coming up with any percentage you may need on the GMAT.

Tens, Fives and Ones

Just like 20% is easy (once you have 10%), 5% and 1% are simple, as well. If you know that 10% = $6.50, you're one small step away from knowing that 5% = $3.25 and 1% = $0.65. So, if you wanted to calculate 16% (and the receipt didn't conveniently show 8% sales tax!), you could simply add the three:

$6.50 + $3.25 + $0.65 = $10.40.

That isn't the only way to get to 16%. You could start by finding 20% (remember, double 10%) and subtract 4% (in other words, one percent, four times), as follows:

($6.50)(2) � ($0.65)(4) = $13.00 - $2.60 = $10.40

Any number can be expressed as a combination of tens and ones. It may be easier to use fives, as well. Once you know that 45 = 10(4) + 5, or than 28 = 10(3) � 1(2), you're just a couple of easy steps away from calculating a percentage.

Answer 3

ok - say an item is $100 and you need to add 5% sales tax.  You need to find out what that is to add it.  5% = .05 = 5/100 -   so you multiply 100 by .05 and you get 5.00.  The item would be $105 with tax.

You can use that with any number.  Usually in sales there are standard amounts like sales tax or discount amounts.  Try doing those at home or write a little cheat sheet to get you going.  Before you know it you will not need that calculator.  Good luck!

Answer 4

If you were trying to find 12% of £52, you would do 52 x 0.12