Numbers: before the decimal

Let’s look again at the format of our numbers. It’s crucial that you understand why they look like they do.

The complete Johnny.Decimal number

Just as a reminder, every Johnny.Decimal number looks like this.

23.24   31.70
22.39   13.04
31.71   21.02
22.38   13.03
23.21   23.22
32.56   12.34
12.35   21.01
32.55   23.23

In words, we have any two digits, followed by a decimal point, followed by two more digits.

Here are a bunch of random numbers from a theoretical system.

Group things together (categories)

Johnny.Decimal is all about grouping similar things together, so let’s start to do that.

All the 12 numbers      All the 13 numbers
        12.34   12.35           13.03   13.04

All the 21 numbers      All the 22 numbers
        21.01   21.02           22.38   22.39

All the 23 numbers      All the 31 numbers
        23.21   23.22           31.70   31.71
        23.23   23.24

All the 32 numbers
        32.55   32.56

Do it again (areas)

That’s starting to look more like something organised and a bit less like a bunch of random numbers. Let’s take it one step further.

All the 10-19 numbers
   All the 12 numbers
           12.34   12.35
   All the 13 numbers
           13.03   13.04

All the 20-29 numbers
   All the 21 numbers
           21.01   21.02
   All the 22 numbers
           22.38   22.39
   All the 23 numbers
           23.21   23.22
           23.23   23.24

All the 30-39 numbers
   All the 31 numbers
           31.70   31.71
   All the 32 numbers
           32.55   32.56


Finder window showing the numbers as above

You can almost imagine this looking like a set of folders.

If you didn’t care about anything except the 22 numbers, you could just collapse the others like this.

Of course, we’ve done this backwards

When we decide to organise something with Johnny.Decimal, we don’t start with a bunch of numbers. We start like this:

Let’s use a small company as an example, and write it out minus the numbers.

Folder                              This is a...
Finance                             AREA
    Tax returns                     CATEGORY
    Payroll                         CATEGORY
        September ’17 payroll       UNIQUE THING
        October ’17 payroll         UNIQUE THING
    Bookkeeping                     CATEGORY
Administration                      AREA
    Company registration            CATEGORY
    Contracts                       CATEGORY
        Cleaning contract           UNIQUE THING
        Office lease                UNIQUE THING
    Staffing                        CATEGORY
Marketing                           AREA
    ...etc.                         ...etc.

All we really do with Johnny.Decimal—and if at this point you’ve realised this and are thinking, “hang on, all he’s done is put numbers in front of things” well then you’re not far wrong—is put numbers in front of things.

But that is everything. It transforms the way you think about and use everything. Trust me.

Let’s put numbers in front of the system we just built above.

Folder                              This is a...
10-19 Finance                       AREA
   11 Tax returns                   CATEGORY
   12 Payroll                       CATEGORY
      12.01 September ’17 payroll   FULL J.D ID
      12.02 October ’17 payroll     FULL J.D ID
   13 Bookkeeping                   CATEGORY

20-29 Administration                AREA
   21 Company registration          CATEGORY
   22 Contracts                     CATEGORY
      22.01 Cleaning contract       FULL J.D ID
      22.02 Office lease            FULL J.D ID
   23 Staffing                      CATEGORY

30-39 Marketing                     AREA
   ...etc.                         ...etc.

So long, cursed alphabet

What does this achieve? For one, it’s removed our dependence on the alphabet. The alphabet is a fine thing but it’s a terrible way to sort your files because things move around. Today we have:


...and tomorrow the exports department come along and do this:

Exports        ← new folder!

...and Finance isn’t the second thing in the list any more. This sounds like a small thing, but it makes it impossible for your brain to learn where something will be.

The Johnny.Decimal version

This is better:

10-19 Administration
20-29 Finance
30-39 Marketing
40-49 Exports

Because our folders all start with a number, they’ll sort in very predictable way1. This concept applies throughout the system.

1.  I’ve seen many shared drives with numbers at the beginning of the folders: people are already solving the curse of the alphabet. They’re just not going far enough.

20, 60, 30, 90, whatever

At this point you might be wondering, well, why is Finance all of the numbers from 20-29 and why is Exports 40-49? What do those numbers mean? And the answer is that they mean nothing. They’re just numbers. 40 isn’t better or worse than 20.

In summary

On this page I’ve talked mostly about the way that we structure our areas and categories. By now you should have a good high-level understanding. You have categories of things and each category belongs to one area only. Areas group categories together.

All of this happens before the decimal. Those two digits of the number are the category, and the first digit of the number tells you which area it’s in.

What we’ve done here is organise a bunch of ‘stuff’ in to something with structure; we’ve created, essentially, a very simple database.