Binary Fingers!

Forget about counting to 10 on your fingers ... you can count past 1,000 if you want!

Right Hand

With just your right hand you can count to 31:



No fingers up is 0 No fingers up is

Thumb is 1 Thumb is

Index finger is 2 Index finger is

2 and 1

makes 3 2 and 1makes

Middle finger is 4 Middle finger is

Add your thumb

for 5 Add your thumbfor

4 and

2 makes 6 4 and2 makes

4 and 2 and 1

makes 7 4 and 2 and 1makes

Fourth finger is 8 Fourth finger is

... and continue the pattern: add your thumb (+1) to make 9,

or add your index finger (+2) to make 10

or add thumb (+1) and index finger (+2) to make 11

etc.

In fact you are counting in Binary:

Number Made by 1 1 up 2 2 up 3 2+1 up up 4 4 up 5 4+1 up up 6 4+2 up up 7 4+2+1 up up up 8 8 up 9 8+1 up up 10 8+2 up up 11 8+2+1 up up up 12 8+4 up up 13 8+4+1 up up up 14 8+4+2 up up up 15 8+4+2+1 up up up up 16 16 up 17 16+1 up up etc....

Here are some more examples:

16+8+2

makes 26

16+8+4+2

makes 30

Why?

So you can count to bigger numbers when you don't have a pencil or paper.

You can also "remember" numbers by holding your fingers in the right way.

Or you can show someone a secret number using just your hand (or hands, see later).

Your Turn

Practice counting from 0 to 31 on your fingers, just like above. Do it many times until it becomes easy. When you can do it well, demonstrate it to your friends!

Left Hand

Want bigger numbers? Your left hand can help:

Now we can use all 10 fingers to make numbers like these:

32+2

makes 34

32+16+8+4

makes 60

512+256+32+2+1

makes 803

And lastly, what happens when all fingers are up?

512+256+128+64+32+16+8+4+2+1

makes 1,023

So now you can count just past 1,000 using only 10 fingers. Wow.

Practice this over the next few days ... you will gain a new skill and also find binary much easier to understand.