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The numbers game – mnemonic devices for large numbers

When memorising numbers, a lot of memory athletes use approaches built on two main systems – the Major system and the DOMINIC system.

The Major System

Unbelievably, this system has been around for hundreds of years, but its current form was first publicised with the rules below by Francis Fauvel Gouraud.

The numbers 0-9 correspond to consonants – phonetic sounds, rather than specific letters. Vowels and the letters W, H and Y are ignored.

The number to letter rules:

  • 0 – Z, S, soft sounding C
  • 1 – T or D
  • 2 – N
  • 3 – M
  • 4 – R
  • 5 – L
  • 6 – J, CH, SH, soft G
  • 7 – K, CK, hard G or C, Q
  • 8 – F, PH, V
  • 9 – P or B

If you wanted to memorise the number fifty six, you might choose the word LeeCH. Longer words can be used represent bigger numbers (584 – LoVeR) and you can combine or chain mental objects together to signify much longer numbers.


  • Allows encoding of multiple digits within a single word
  • You only need to memorise the rules in order to decode objects


  • Some of the number to letter rules are difficult to remember
  • Not all numbers make easily recognisable images
  • A mental object needs to be decoded as a specific word (hut, shed and shack would be different numbers)

The DOMINIC System

Invented by former world memory champion Dominic O’Brien, this beautifully simple and elegant system appears in his book ‘How to pass exams’. I like it a great deal, especially for four digit numbers, and have used it myself in the past.

In simple terms, numbers are converted to pairs of letters, which are then converted into the initials of celebrities. For example, 1608 converts to AS and OH which, depending on the celebrities you choose, might be Adam Sandler and Oliver Hardy.

The number to letter rules:

  • 0 – O (zero looks like an ‘O’)
  • 1 – A
  • 2 – B
  • 3 – C
  • 4 – D
  • 5 – E
  • 6 – S (six begins with an ‘S’)
  • 7 – G
  • 8 – H
  • 9 – N (nine begins with an ‘N’)

Each celebrity has a signature object, for Oliver Hardy, this might be a piano stuck halfway up a staircase. When you need to remember four digits, combine the first celebrity with the object belonging to the second celebrity. So, 1608 would be an image of Adam Sandler trying to push a piano up some stairs.

Single digits are memorised with a zero in front, so 8 can be represented by Oliver Hardy. This also allows you to encode three digit numbers.


  • If you know the pegs, the mental images are obvious and require no effort to create
  • The pegs create very memorable mnemonics
  • The number to letter rules are very simple and intuitive


  • You need to memorise a hundred pegs to go beyond two digit numbers
  • It’s difficult to find well known celebrities to match all the digits
  • With very long numbers, it can be tricky to chain groups together

In the next post I’m going to look at how these systems are used in memory competitions, and the approach I’d recommend for students.

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