I wrote a ton on this subject for ToutRetenir.com and unfortunately I can’t translate most of it now, but here are the main points. Numbers and cards are memorized mostly the same way one memorizes anything else: by converting the information into some unusual images and by storing those images in some well-known place that you can mentally walk through later on.
If you aren’t already familiar with memory techniques, you might want to start by reading:
- The latest section about mnemonics in this Memorization 101 article
- This article about how to memorize a list of words
- Some sections of This article about how to create more memorable images
My stories for remembering a deck of cards or for a set of 100 digits will look very similar to my stories for a list of 50 random words. If you haven’t yet learned how to memorize a list of words, you should do that first. If you can manage to remember 50 words in order, you can also manage to remember 100 digits or a full deck of cards. In your mind, the number of images involved will be about the same. The process will be harder at first. But with some practice, memorizing cards and numbers will become easier than just about anything else.
Why is it harder at first? Because unlike words, numbers and cards can’t easily be converted into images without using some pre-established system. If you want, you can start using this sample number systems (or this one using an alternative code) right now. It will work, but the process will be slow because you’ll always have to refer to the sheet. If you want to become quick and efficient, you will need to design your own personalized system, learn it and practice it.
But as I said, once the preliminary work is done and you’ve practiced enough, it’s sort of amazing how easy the process can become. Again it will be similar to the memorization of a list of 50 words, except that the process of converting numbers into images will be almost automatic. With no possible ambiguities. Using combinations of images that you’ve chosen and that are particularly memorable to you.
Semi-important precision: This article seems very long mostly because I cover many different methods. But once you’ve chosen a particular method and you manage get to work, you’ll see that the memorization of numbers and playing cards isn’t quite as scary and complex as it may seem.
Which systems should you choose?
There are many different systems one can choose to use. Here are the main options that I will be presenting on this page, ordered from the simplest to learn to the most time-consuming:
- Option 1 – The simple system – Just 10 images chosen for each digit from 0 to 9.
- Option 2- Learning a letter-code system and using it to improvise images whenever you need to remember some numbers.
- Option 3 – A 1-digit PAO System, with just 10 characters, 10 actions and 10 objects.
- Option 4 – 100 predetermined images chosen with the help of a letter-code system.
- Option 5 – 100 predetermined images chosen more or less arbitrarily, without any letter-code system.
- Option 6 – A 2-digit PAO system, with 100 characters, 100 actions and 100 objects.
- Option 7 – 1000 predetermined images chosen with the help of a letter-code system
So which system should you choose? It depends on your personal preferences, your goals and how much time and energy you’re willing to invest. For each system below, check out the opening “Recommended for” part for my thoughts regarding whether or not this particular system is the right choice for you.
If you don’t want to have to overthink the process, here are my official recommendations:
- Option 4 – 100 images chosen with the help of a letter-code – is the one I’m most inclined to recommend. If you’re reading this page, chances are you’re motivated enough to go for that option. That’s more than enough to become very efficient in any situation where numbers are involved. And it doesn’t take nearly as much work as one might think. I think the effort-to-result ratio is extremely good here. It’s possible to become extremely fast without ever using anything else. Even for people who don’t care too much about speed, I think it remains a worthwhile investment in the medium and long term. It’s also possible to start with this system and later on decide to upgrade it either to a PAO system or, for the extremely committed people, a 3-digit system. After I’ll become dictator of the Universe, schools will start forcing all kids to build such a system or something equivalent. Everyone will thank me later.
- A 2-digit PAO system is also a great option for many people, particularly if you enjoy the structure it provides and if speed and quick improvements are important for you. However, for various reasons that I’ll explain later, I’m less tempted to recommend it than I used to be.
- If you don’t care too much about numbers and you only want to be able able to remember a few numbers here and there, then either option 2 or 3 should be perfect for you. You will never be able to memorize 100 digits very quickly with just that, but it will be good enough for the vast majority of situations you’re likely to encounter, like wanting to memorize your credit card numbers, your social security numbers, some passwords, some dates of birth and so on.
How to use your new system to remember playing cards
Want to memorize a deck of cards? You could build a PAO system just for that by following the advice in this video or this article. But personally, I think it would be simpler and more efficient to build a system for numbers with at least 100 images for 00 to 99 and use 52 of those images for both cards and numbers. Cards and numbers will then become variations of the same discipline. If you already have a system for numbers, you can learn to memorize cards in just a few minutes.
*While I am in favor of using the same system for both cards and numbers, I think it might make sense for many people to first learn to memorize cards before moving on to numbers. Learning 52 images is significantly faster and easier than learning 100. You could even start with memorizing solely the 12 face cards. The main advantage here is that you really won’t have to wait long before you start practicing and developing your memory skills. And perhaps those early experiences will help you develop a better 100-image number system later on?
Option 1 – Simple 10-image system
Recommended for: Young kids. Also good for people who want to use it as a complement to their 100-image system.
Basic explanations: Here you just choose one image for every digit from 0 to 9. You can choose those 10 images arbitrarily, by basing yourself on the shape of the number (like in the image above), on its sonority (zero = Zorro, one = gun, two = shoe and so on) or on some other kind of association.
Pros and cons: This isn’t great for long series of numbers, but it should be good enough for many situations in daily life. If you have to remember to take bus 63, you can imagine an elephant (6) being arrested (3) right at your bus stop.
Option 2 – A number-sounds code used with improvised images
Recommended for: Perfect for people who don’t care about speed and who only want to remember a few numbers here and there, when it’s useful or necessary.
Basic explanations: Every digit from 0 to 9 has a consonant sound associated to it. 3 is usually an M, 1 is usually a T or a D (two similar sounds). To remember 31, you’ll need to use those M + T or D sounds to improvise an image. A MoTocycle maybe? A MuTant? A MiNe? By far the most well-known letter-code system is called the Major system, but there are others.
Pros and cons: You can learn a number-sounds system and start using it in just a few minutes! It’s good enough for your needs if you aren’t competing and you don’t want to memorize a thousand digits of Pi or something. It might also be a decent creativity exercise. However, using this method is slower and it takes more mental energy than using pre-determined images.
Option 3 – A 1-digit PAO system
Recommended for: Like option 2, this is perfect for people who only want to remember a few numbers here and there, when it’s useful or necessary. You should go with option 2 if you prefer to improvise your images whenever you need them. You should go with option 3 (this one) if you prefer your images to be predetermined. Option 3 might also be good as a “first step”, as a form of training and experimentation before moving on to a more complex system.
Basic explanations: So how does that supposedly simple 1-digit PAO system works? PAO stands for Person-Action-Object. Each number from 0 to 9 is pre-assigned to a character, doing some action to some object. You choose whatever characters and actions and objects you prefer to use. If you want to remember a 3 digit number like 942, you would use the character for the first digit (9, so Osama Bin Laden in the example below) doing the action of the second digit (4, so swimming) using the object of the third digit (2, so some disgusting cat litter box). You would then place Bin Laden swimming through the cat litter box on your kitchen table or wherever you want in your memory palace. The next Person-Action-Object would appear somewhere nearby and so on. Your small 25 loci 5 rooms memory palace could then comfortably hold 75 digits. Let’s say you’re more down-to-earth and practical and you just want to remember that your friend’s address is 873 Berri street, you could just imagine Eric Cartman breakdancing with the American flag (character for 8, action for 7 and object for 3) among a bung of berries (for Berri street) in front of your friend’s apartment and voilà! If you want to remember those 50 keys dates from world history, build a memory palace with 50 loci. In each of those locus you would improvise an image to represent the event and you would add a character from your PAO for the century, an action for the decade and an object for the year. Hopefully you don’t need a mnemonic to remember the millenium. If you review them right like I explained before, those 50 dates will stay in your long-term memory for as long as you want to.
Here’s an example of a hypothetical full 1-digit PAO system:
Option 4 – 100 predetermined images chosen with a number-sound code
If you’re motivated enough, this is the option that I recommend to most people. I think the effort/result ratio is particularly excellent here.
Option 5 – 100 predetermined images chosen without a number-sound code
Like option 4, but the images are chosen in any way you like. You can use different forms of associations, categories of your choice (30 to 39 can all be related to Star Wars for example) or just pick images you like and assign them to numbers any way you want.
- Remarkably effective and fun once the system is well learned.
- Complete or near-complete freedom in choosing your images.
- Takes much longer to learn.
- Requires more regular maintenance.
- It’s easier to get stuck if you forget what a particular number is.
Option 6 – A 2-digit PAO system
Just like option 3, but with 10 times the number of characters, actions and objects. 300 images in total. A 2-digit PAO system is very fun and very efficient, but it will take a long enough while before using it can become second nature. The system also does some of the creative work for you, which I think is both an upside and a downside. It works great, but I now think you should build such a system only if the quick memorization of numbers and cards are a priority for you. See this video for more details.
Option 7 – 1000 images chosen with a number-sound code (for insane people only)
Recommended for: Only worth it for crazy insane people who have no life outside of memory sports. Ok I’m partly joking with that statement. I know that plenty of awesome people with well-balanced lives have successfully built such a system. But I now honestly think that 99.9%+ of people shouldn’t do the same. I would even say that 90% or 95%+ of people who are passionate about memory techniques shouldn’t build such a system. I say that as someone who has spent a decent chunk of the last few years building and learning and modifying and relearning and practicing a 1000-image system along with a 2-card system. I love it and it’s awesome (although for now I still remain slower than I used to be with PAO). I’m looking forward to using it a million times in the future, but I probably wouldn’t go through that whole endless project again if I were to travel back in time. [Blog post explaining why coming soonish].
Basic explanations: Just like option 4, but with 10x the number of images and 1000x the amount of time and energy needed to master the whole thing. There’s a lot more to say, but that’s the gist of it. For those who still want to go through such a crazy project, I’ll sooner or later add more detailed explanations and advice to help you out.
How to learn your new system
How to become faster and more efficient
- Read the article I just linked to about how to learn your new system and attempt some of those exercises regularly. Even after when you know your system very well, those exercises will help you become even faster. In a week, I usually spend very little time memorizing numbers (often not at all for long periods of time), but I more regularly spend a short 5 minutes doing a quick review exercise of my system on the subway. In addition to being short and easy, these exercises help to make us progressively faster and more efficient, with a minimum of time and effort.
- If you haven’t done so already, I recommend that you check out this article about how to memorize a list of words. The process of memorizing words and numbers is similar enough and you will pick up many useful tips and techniques.
- Build some new memory palaces designed for training, review their configuration, improve them if necessary and practice using them at least once a while.
- Study the relevant parts of this article about how to create more memorable images and improve your skills.
A few last precisions for now:
- Do we need to create ten different images for 01 to 09 and ten more for 0 to 9? If your system has 100 images or more, the answer is yes. This allows you to differentiate the memorization of 50-45-9 with that of 50-45-09. It also allows you to have at least two possible choices of images when you only want to remember one number from 0 to 9. For the numbers 0-9, I recommend either using just a simple 10-image system (option 1) or using your number-sound code if you have one. That remains my recommendation even if you’re using a PAO system. Although there is nothing to stop you from having ten characters and actions and objects for 0 to 9 and ten more for 01 to 09, the effort isn’t worth it.
- Just in case: you can choose to encode 56788 as 56-78-8 or as 5-67-88, whatever.
- Some people choose a system that they will never change. Personally, I made many changes to my system until I became completely satisfied with each of these components. With practice, you may find that, for example, you tend to confuse your Trinity (Matrix) character with your Catwoman character. You might want to get rid of Trinity and choose another character, or you might decide that Trinity should wear a soccer helmet from now on, to minimize the chance of confusion. Changing some details is almost always fine. If you decide that from now on, Shakira is wearing a short green skirt while her action and object remain the same, I don’t see any downside to that decision. More important changes (from now on, Shakira will be 32 instead of 44, and she’ll be using a chainsaw instead of a hula hoop) will slow you down in the short term while they may or may not help you in the medium and long term. Just make sure you don’t do like I did and you don’t fall into those endless perfectionism traps.
- If you have a system with 100 or more images, I recommend memorizing at least one small set of numbers once a week to keep it from getting rusty. Or, if you prefer, you can just do some of the exercises suggested in the “How to learn your number and card system” article. As I’ve said before, these exercises are very effective and require less time and mental energy than memorization. Also, get into the habit of turning into images some of the numbers you are confronted with in your daily life. Over time, you will come to know each element of your system as well as you know your mother’s name. Practicing will then continue to be useful, but it will cease to be necessary.
- Just in case you missed the link, here’s how your number memorization system can also be used to memorize playing cards.