What is the best mental math and memory system?

Hello I am a 14 year old male high-school student from New Zealand and I am trying to find an effective system for me to do mental mathematics and a memory system to help me memorise books and movies for my own enjoyment and for school work
my goals are as follows
addition to be able to add atleast 5 numbers of various sizes (biggest being 6-7didjets) with only having to see the problem once or twice
subtraction to be able to subtract 3-4 4-5 didjet numbers from another larger number (7 or so didjets)
multiplication to be able to multipy a 6 ddjet number by a 6 didjet number
division I want to be able to devide a 6 didjet number by a 5 didjet number
squaring I wish to be able to squarea 5 didjet number and also get the square root of a 5 didjet number (times by itself and work out what numer times by itself makes this number)
and to be able to multiply a 6 didjet number to atleast the power of 5
I also want to learn a efficient mnemonics system to help remember the numbers im working with (like Arthur Benjamin) and also a effective memory system to help me memorise cards for card games like poker as well as memorise a book after reading it once and to be able to read a 300 page book in 1 hr or 1hr and a half
I dont plan on learning all this immediately I expect it will take ages to learn it all but I hope in a matter of months I will be able to do mental math effectively and be partway to my goal of memorising
one last note I have Aphantasia and prosopagnosia so any tips that dont involve images more like sounds will help (I can’t recall exact sounds but will know how to make them so that might help and I cant form images in my mind I just kind of hear myself and its very quiet if you have tips to make it louder) thank you for reading and I eagerly await your help!


You can use the search function to find what you’re looking for. All of this has been discussed on the forum before. If you got questions after having read the available information just post something more detailed here and people will help you out.

…also, the word is: digit


thank you for the reply and I am aware this has been discussed before but nobody has given information that helps me in my search and also I have dyspraxia a disability related to autism so I am aware of my spelling mistakes.

User @Kinma has many good topics on mental math, they are all worth reading.


thank you
I may try to have them give me some advice aswell as read their posts this is genuinely helpful

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For number systems, you might want to try the Major System or Shaper System. See how to memorize numbers for an overview.

You can modify your number system to memorize cards. Check out the free ebook for information on that.

If you’re interested in competing in card memorization, you might be interested in expanding the 1-card system from the ebook into a PAO System or a 2-card system like the Shadow System or Ben System.

Thank you if I am to compete first I need to learn an effective system so this helps

“…a book after reading it once and to be able to read a 300 page book in 1 hr or 1hr and a half”

Speed reading?

The book Breakthrough Rapid Reading By Peter Kump is good

Perfect thankyou

You wanna tell me that in the entire #mental-calculation category or using the forum search you could’t find anything?

Funny… because the Mental Calculation World Cup has the disciplines 10 by 10 addition and 8 by 8 digit multiplication, which was been discussed quite a bit before:


I’m a bit surprised that none of these posts had anything in them that would answer your questions.