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# How to Work Out Percentages - Some Tricks to Help You Work Out Percentages Without A Calculator

## Author's Note

__I f you're looking for conventional/standard ways to do percent problems you'll find several links to "real" math sites by scrolling down toward the end of the main part of this Hub.__ That isn't the purpose of this Hub; and although I've considered including more conventional approaches here, I think it's most fair to people looking for help with percent problems to direct them to sites that do a better job showing those conventional approaches than I can. After all, that's the sole purpose of those sites. For more on the purpose/intent of this Hub see "More About This Hub" below.

## Some Handy "Tricks" for Doing "Percent Problems"

**A Few Notes On The Basics:**

In order to find x percent of any number the general way of doing that is to multiply the number by the percentage. Since percentage means hundredths of any number, percentages are written with the decimal point moved two places toward the left-hand side. With whole numbers the decimal point does not show, and since moving the decimal point over one place would indicate tenths, examples of how percentages should be written before multiplying are: .05 (five percent) or .20 (20 percent). An example is find 40% of 80: Multiply 80 (since its a whole number you don't see the decimal point) by 0.40 (which is how percentages can be written, although the 0 before the decimal point isn't really necessary). The answer is 32.

Multiplying any number by any percentage (and remembering to include the decimal points in the answer) will give the percentage.

**Quick Tricks**

Quick tricks for finding percentages can be used. For example, if one wants to find 30% of a number s/he can start with the original number, mentally move the decimal point over one place (in order to find 10% really quickly) and then multiply that 10% by 3 (because 10 x 3 =30). Any time the percentage involved is divisible by 10 this trick can be used.

Another quick trick for finding 5 percent is to move the decimal point over one place (again, to find 10 percent easily) and divide that result in half (because half of 10 is 5).

Finding percentages that are multiples of 5 (for example, 25) can be done in three steps: Move the decimal point over one place to get 10%, divide that figure in half to get 5%, and then mulitply that figure by 5 (because 5 x 5 = 25).

Also, knowing that 10% equals 1/10th of any number means that finding 10% can also be done by dividing by 10.

Most people are familiar with the fact that a quarter (25 cents) is 1/4th of 100 and that 50 cents is 1/2 of 100. Keeping those basics in mind, one can easy remember that finding 25% of any number means dividing it by 4 and that finding 50% of any number means dividing it by 2.

In the case of something like 75% figuring that out could be done either by using the above divisible-by-5 method or, if its easier, finding 25% and multiplying that by 3 (because 3 x 25 = 75).

A trick for finding 40% might be moving the decimal point over one to get 10% and either remembering that figure or writing it down. Then divide the number for which you're trying to find 40% of by 2. Once you have half of the number subtract that 10% you first figured out - and you've got your 40%.

The finding-10% trick/aid can also be turned into a finding=1% trick/aid. If you move the decimal point over two places you have found 1% of any number. You can easily multiply that 1% to get any other percentage simply by asking "how many 1's are in this percentage?". For example, to find 20 percent you can first find 1% and then multiply that 1% by the 20 (because there are 20 1's in 20). This will also let you find, for example, the 20%.

Finally, there is the issue of figuring out a tip in a restaurant. Again, the quick way (for 15%) is to move the decimal over one place to get the 10%, divide the 10% to figure out what 5% is, and then add together the 10% and 5%. A 20% tip is easier - just get the 10% and multiply it by 2.

## Percentages - Links

## Math Help

## A Few Primary-School Math Programs

## More About This Hub

This Hub was originally written to show "quick mental tricks" for doing percent problems. It was written with adults in mind and in response to a request. It was not intended to offer more than those quick tricks for common percent problems. The aim was to offer people those tricks they could use in situations involving things like shopping and tipping. Sometimes we need a quick way to figure a tip or sales tax. Sometimes we want to know how much a product will cost when we learn it has a "75%-off price". The aim was to offer a few simple ways people can do percentage problems in their head that can come in handy, and that don't show up too frequently in the "standard" search on doing percentage problems.

When I wrote the Hub I didn't change the wording in the request, and now that it has taken on a nature/life of its own it is clear the title is no longer appropriate or sufficient (to describe the content). I could change the title, of course, but the Hub has found its place in search engines and has turned out to help a lot of people (usually young students) who were having some trouble "getting" how to do percentages. As a result, I don't want to change the title and risk the Hub's "getting lost to the ages".

The nature of the Hub evolved, though, because readers began asking for elaboration on the original approach (the "mental tricks") . From there, readers began asking about percent problems that went beyond the kind one would do using those "mental tricks".

Originally, I had approached writing this Hub (in answer to that question/request someone had posted) as if I were sitting at the dining room table, trying to help a middle-school or junior-high student understand percentage problems. So, it started out "folksy" and in terms that wouldn't show up in math books; and as things evolved and all those questions/comments continued to be posted, I continued to use the same approach.

The way I've seen it, if someone is asking how to figure a percent problem there's a good chance it's because they haven't already become comfortable "doing percents" as taught/being taught in school. So, as questions about finding percents have continued to come in (and as a lot of them have gone way beyond the original intent of this Hub), I've found myself using whatever words or combination of words and techniques I can "pull out of the air" in an attempt to make understanding what "is going on behind a percent problem". People who have trouble "getting" some things in math have that trouble because things like equations on paper don't mean anything to them.

In any case, the Hub has taken directions that weren't the original intent. At the same time, when new questions have been posted I've just figured, "It's easy enough for me to just answer them." As a result, the comments section of this Hub has become very much aimed at people for whom math class and math books haven't happened to be very effective (or wasn't effective enough for them to remember if they were students years ago).

The point is, if you're comfortable with math and having no particular challenge learning from math teachers or books, 1. You either don't need this Hub or else you need one of those conventional "how-to-do-math" sites, from which you can easily find that little extra bit of information you need., and 2. There's a good chance you'll find this particular absolutely "wacky".

If you've always been comfortable learning math there's also a good chance you can't imagine how a perfectly "smart" student may have trouble learning one thing or another, only because an adult hasn't figured out that he needs someone to think up a different way of presenting one thing or another.

Adults who may have, as students, once hit a "stumbling block" on one math thing or another, and adults who have ever had to watch a student struggle with one kind of problem or another (or most of them), will understand why I've left all the questions and answers in the "Comment" section on this Hub.

## More Math Help

## Comments

omg tanks i was strugaling!

I'm doing a test tomorrow on this stuff, and I'm not sure how to work out things like 27 out of 40 as a percentage, I understand that to find 13 out of 50 as a percentage is just how many times can you fit 50 into 100 which is 2 then times 13 by 2 as well to get the answer I'm just very confused on how to find out numbers like 40 and others that you cant fit equally into 100 :/ Can anybody help pleaseee!

it is a awesome site

Lisa HW, Your dedication to this posting has been astounding to me. Your efforts are definitely appreciated!

exuse me, how do you work out 21 percent of something? i'm very stuck and urgently need help! thank you. :)

Sorry the example was for you to let me know what the 65% and the 69% would be as they are both only worth 25% or 35% of 60%.

So what would 65% be as a 25% of 60% and

what would 69% be as a 35% of 60%

if that makes sense?

obviously if the grade was 25%,25%,50% it would make it easier as we would merely half or quarter the grade to find out what it is of the %age.

Thanks.

Yes Lisa,

You are quite right in your second-guessing.

40% of the whole module comes from the one exam result

and the other 60% is coming from two parts - online test 35% of that 60% and the assignment being the 35% of the 60%. Each of the pieces of work are worth 100 marks.

40% and 60% adding together to make the whole 100% for the module.

Ok so let's just say I throw some random numbers out here for you to make understanding a bit simpler for me as im currently not well AT ALL so this is all still a bit confusing,

These are examples;

For the 25% of the 60% online test I got 65%(MARKS OUT OF 100)

For the 35% of the 60% assignment I got 69%(MARKS OUT OF 100)

For the 40% exam I got 73% (MARKS OUT OF 100)

Thanks for the help so far..!! x

For my university grades this year in one module they have decided to make life difficult for us.

The total marks come in the form of

a test (25% of 60%)

an assignment (35% of 60%)

an examination (40%)

Quite clearly the 40% won't be the difficult one to figure out, but I'm a bit baffled on figuring the 25% and 35% of 60%.. Help here please?

Hey lisa just loved the refresher. I always get befuddled when I go to the market and it is a 30% off sale. Ha Ha. Now I can remember how to work that out to see what the savings would be. Thanks.

Good Post!

If you know what 15% of an amount is, how can you find out what the total amount is (100%)? I use to know how to figure it when I was in school but don't remember it now.

Hi! Do you know the percentage of Google finding- "how to work out percentages" - this hub? 99.999999% ! -- Thanks

18 people as top management working in a company of a total manpower 1570

what is percentage of the management

how it calculate

Hi Lisa. This may not affect you but thanks to ur site I got 97% on my percentage and decimal test I showed my friend the site and he showed the teacher now the page is in our school bookmarks lol

hi Sean

again there is an easier way of working out your answer

original price 240 special offer price 210

240 - 210 = 30

then 30/240 = 0.125 x 100 = 12.5%

cheers

sean w

So how would you do a percent decrease or increase with an unknown percentage. Lets say you went to buy a dining room table that originally sold for $240 and since it was a floor model it was reduced to $210, what is the percent decrease from the original price?

how do you work out 40% of 45 ?

Dang Lisa you so smart lol I hope you remember me from comments above you rule

Hey, Im a 6th grader, I suck at math. So I read a few comments and stuff and went oh, I can do this!! so using my calculator I divide .5 into 763...and got 1678...I DONT KNOW HOW!!! Help!!

Lol sorry so are you like 60? That sounds right lol I'm just wondering cause iv never met a person as knowledgeable as you haha

this is stupid i said suppose u don't no the percentage eg.10% and they just say find the percentage of 15

Hehe this is great Lisa but if your teachers are born late 1800s aren't you like 80? Not that it's bad because you know so so much

Wow thanks for answering I get it now your the best and also it's cool how you still answer questions even though you made this 2 years ago!!! Lots of people just make a site answer 2 questions and leave. You need a donation button lol how are u so smart? How did u learn I really need to know because I get slot of presure from parents cause there both doctors but anyway I really appreciate what you do for us ur a legend u rock

Lisa you have a great site your really smart! But is doing a percentagethe calculaterway which is making it a decimal like .45 of 20 really hard? Because i don't get the timeing by 100 thing please reply!!!

If your beginning amount is reduced by .10% and the result is 1,605,837; what was the beginning amount? Also is the .10% 1/tenth of a percent or is it 10 percent?

omg i totally hate percentages well anyway thanx 4 the lesson i learned something about this subject!....

How do you work out the percentage increase/decrease from one number to another?

this isn't the one i am looking for.i am looking for the one that is for the price nat decimals

losers al of u

thanks for ur help

Hi I am wanting to know if a question asks;if you got $60.00 and spent $14.50,what is the percentage you spent(14.50)what's the fastest way to calculate this?thank you

thanks this is really nice way very eassy.............

oh and one more think sorry Lisa

1199 is the price and i picked it up for $700 what is that as a discount off 1199? I know 30% off 1000 is 700

I'm a 6th this year and when i read your working out strategy, I didn't really get it. Can you explain it a little shorter and easier to understand?

Thanks!

Thanks a lot for that Lisa

I think i might have made a mistake in my question though here is what i'm trying to do:

I sold 37 units this month and the same month last year i sold 33 so what is the % increase here? Also lets say i sold 875 last year and only 370 this year how do i wrk that out as a negative??

Sorry and many thanks!

hi Lisa

i need to work out what 310 is as a percentage of 387

I'm not sure how to work out negative percentages??

Thanks

thank you

great thanx yo rock i totally get it

Thank you for this. Clearly written and easy to understand -- even for someone mathematically challenged such as myself.

i really had problems. thanks for this great hub

you keep mentioning move the decimal point over one....LEFT OR RIGHT ? Just to make it perfectly clear.......Ü

Just what I was looking for thanks a lot:)

very nice article.....

keep up the good work ....

thanks ....

Good article on working out percentages thanks, maryladd

In the words of R. Kelly, "Everybody feelin freakyyyyy!!!!!"

Excellent hub topic.I think your tips gonna help me to figure out restaurant tip in a few seconds.

Very well written hub .....

very much informative ......

Thank you very much for your great hub, for good advice, good wishes and support. Thanks for sharing your experience with all of us.

im really struggling the best way to work out this problem please, please help out of 800 shoppers 300 shop more than three times a week. What percentage of the shoppers shop more than three times a week? i know theres got to be an easy way

Ok, how do I find out what the percentage is of something? If I am making something and I add 3.5 oz. base ingredients and add.5 oz. of another ingredient, what is the percentage of the .5 oz to the whole thing?

How would you work out 22% of 25%???

all sounds like archish to me (language bezzies made up don't get it) thanx though

i still dont get it (:sos:)

How do I determine the percent of each person's percentage of the vote. For example, if a person got 161 votes, how do I get the percentage of that number of votes. It might read 161 or "percentage. What are the steps?

I know how to get percentage of a product discount and so on, no problem.

thanks

i think this site help me a lot but the site was BULLSHIT

That is excellent. I liked it Lisa. As I am looking forward to the Management aptitude exam , this tutorial would be the boon for me.

Thanks for your efforts.

Please do write some other articles on various other tricks.

I appreciate your dedication.

you really help me thank you

i hate it does not helr

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