Percentage Help Excel

[phleb]

Hiya, i know i can rely on you all. what is £450-10%? i have set percentage on excel. but answer comes up as 449.90. thanks x

[Svejk]

£405

[Prudie]

On excel an easy way to get 10% off is to multiply by 0.9. That should give you the correct answer (405 in this case)

[jim360]

10% is just a raw percentage and excel doesn't know what it's 10% of. To get the formula to work you need to enter the following:

"=A1-10%*A1".

Where, say, a1 is the cell with £450.

[jim360]

Oh, and then make sure the cell with that formula in is formatted to display currency.

[Old_Geezer]

I guess it assumes 10% of 100 pence.

But for sure any of the above would work.

[phleb]

Prudie, so i can just multiply 0.9 from any number to get 10% off?

[phleb]

thanks jim, svejk and prudie...x

[Prudie]

Phleb, yes you can

[Peter Pedant]

// Prudie, so i can just multiply 0.9 from any number to get 10% off?//

yes

try it with 100 p ...... 0.9 times 100 is 90 and yup that is 100 - 10%

[phleb]

Thank you Peter and everyone else, i have learnt something new today. I am pretty poor at maths, and i want to be pretty good ;-)

[Old_Geezer]

I guess you didn't do many lessons in percentages.

Yes, 100% is also = 1 Because 100% is a whole one.
10% is thus = 0.1
90% = 0.9

So if you want 90% of 'a number' you calculate 0.9 * 'a number'.

And so on and so forth.

[jim360]

Yes, prudie's suggestion will also work.

There is a direct equivalence between percentages and fractions and decimals, which works in the following way. 10% really just means "10 per 100", or "10 divided by 100". Thus all percentages can instantly by converted into a fraction by taking the number that's the given percentage, and writing it instead as a number over 100. E.g 25% = 25/100, 33% = 33/100 and so on. This is a one-line result (then, if you like, you can simplify the fraction by using rules such as common factors and what have you, so that 10/100 is really 10/(10*10) = 1/10, as a 10 cancels from top and bottom).

The equivalence to decimals works because, for example, 0.1 means "one-tenth", 0.01 means "one-hundredth". Thus, all percentages can also be converted straight into decimals: 10% can be written 0.10, 33% is 0.33, 25% is 0.25 etc. If the percentage given is less than 100% then just scrub the % sign and put "0." before the number and you have the percentage as a decimal number. If the percentage given is greater than 100 then put that decimal point before the final two digits and after the rest, ie 133% = 1.33.

So we can see that prudie's method will work by adapting my formula a bit:

"= A1-10%*A1"

"=A1-0.10*A1" (converting to a decimal).

"=A1*1-0.10*A1" (because we can multiply anything by 1 and get the same thing back)

"=A1*(1-0.10)" (because A1 is a common factor so we can write what's left as a bracket)

"=A1*(1.00-0.10)" (because we can just shove as many 0's after the decimal point as we like without changing the number)

"=A1*0.90" (perform the subtraction)

"=A1*0.9"

Which was prudie's formula.

[Retrochic]

Its a sad reflection on the education system that someone can't work out 10% of a number without the aid of a calculator, then deduct it from the original number. A mental math lesson for the OP :450 put a decimal place (a dot) one number from the right you get 10% = 45 two dots from the right you get 1% 4.50

[Prudie]

After 10 years teaching maths at a secondary modern school and then more years working with a broad spectrum ability of adults in the civil service I can confirm that percentages are an enigma to many.
Phleb just asked how to do it in excel, a perfectly reasonable request.

[zebo]

After reading Rhetrochic's facetious reply, I imagine many people would be put off from asking for help here! I don't think phleb wanted a critique on perceived failures of the education system. Remember, they're only easy if you know the answer.

[-Talbot-]

lol... I love the difference in complexity between, Prudie's and Jim's answers.

[jim360]

If anything prudie's answer is more complex since it requires actually working with percentages. The formula I provided handily sidesteps all the actual thinking and lets Excel do the work for you -- and then the later explanation isn't so much complex as just including every single step that links the two formulas. Hopefully phleb is able to follow it.

[Prudie]

Well 'how' often tends to get you there more easily than 'why'.

[jim360]

True -- ideally the "why" is insightful, though.

[Retrochic]

zebo my reply was not facetious. My son has been able to work out in his head 10% 50% even 25% of a number since he was about 9 years old. The OP has said on other threads they want to work from home doing admin. for clients. I suggest before being let loose on someones Profit and Loss sheets they go do a proper course on Excel and Word.