Us humans are pretty handy with our beloved decimal systems, but computers just don't dig it. It doesn't compute. *They* love that ever-so-wacky *binary* system. They've got good reasons too - Why be a normal human, only able to count to five on one hand, when you can become a faux-cyborg with the ability to count to 31 with only your measly earthling fingers.

Decimal is a *base-10* numbering system. Binary is *base-2*. Base-10 means that the numbers go from 0 to 9 (10 numbers), and when we get to 9 we have to "carry the 1" to the next column. Base-2 goes from 0 to 1.

Yep, binary only gets up to 1 before we need to "carry the 1". Which is a bit confusing, but pretty cool. Counting in binary goes like this: 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010 - that's 0 to 10 in binary.

Remember in primary school when you learned 1's, 10's, 100's etc. for each column? Well in binary the columns go 1's, 2's, 4's, 8's, 16's etc. In base 10 each additional column is 10 times the size of the previous. In binary it is 2 times the size of the previous.

**Decimal:**

```
``` 1000 100 10 1
x **1** **0** **5** **2**
------------------
1000 + 0 + 50 + 2 = 1052

**Binary:**

```
``` 16 8 4 2 1
x **1** **1** **0** **0** **1**
----------------------
16 + 8 + 0 + 0 + 1 = 25

So what's it good for? I don't know. Stuff. As I said, computers like it cause they only really understand 1s and 0s (which is 'on' or 'off' to them). Also you'll be able to understand this t-shirt. But what we are going to use it for is counting up to 31 on one hand. Practical, and impressive at parties.

Have a go at clicking some of the checkboxes in the interactive "cyber-virtu-hand-3000" at the top of the page and see if you can figure it out. Ya get it? hey? Here's how it works: Your fingers become the "columns" from above - pinky=16, ring=8, middle=4, index=2 and thumb=1. No fingers=0. All the other numbers are combinations of fingers. for example, counting to 5 goes like this:

thumb(1), index(2), thumb and index(2+1), middle(4), middle and thumb(4+1).

Practise counting from 1 to 31 a couple-a times and you'll be a pro. And you'll be able to count the number of people at the party that give you that look of simultaneous sympathy and disgust. But you might need both hands for that - 2 hands can count up to 1023!