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This page explains about Binary counting - and
how to convert numbers from base 2 to base 10.
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Having read, Minifig Maths, you
will probably now want to know exactly how binary works.
Binary is the process which computers run on, using 0s and 1s,
or ons and offs. We (humans) commonly use what is known as base 10, we use ten
digits to count with: 0,1,2,3,4,5,6,7,8,9. Binary is base 2, because it uses two
digits to count with: 0,1.
The steps below show you how to convert a number from base 2 to
base 10.
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| Power of 2: |
256
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128
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64
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32
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16
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8
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4
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2
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1
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Step 1: We want to convert 387 into binary.
First of all, we draw a table like the one above. Each column is the column to
the right of it, multiplied by 2. The highest number we need to go to, is the
number just before we get a power of 2 greater than 387. In this, that is 256
(the next number would be 512 and 512>387).
| Power of 2: |
256
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128
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64
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32
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16
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8
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4
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2
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1
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1
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Step 2: Now place a 1 in the first column,
and take the power at the top of the column away from 387. So
387 - 256 = 131.
| Power of 2: |
256
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128
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64
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32
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16
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8
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4
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2
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1
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1
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1
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Step 3: Next, look for the next column along
which has a number smaller than 131. In this case, that is the next column, 128.
131 - 128 = 3
| Power of 2: |
256
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128
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64
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32
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16
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8
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4
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2
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1
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1
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1
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1
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1
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Step 4: Now repeat the process for the rest
of the columns, you will find that you should have a 1 in columns 2 and 1.
3 - 2 = 1 1 - 1 = 0
| Power of 2: |
256
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128
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64
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32
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16
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8
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4
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2
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1
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1
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1
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0
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0
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0
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0
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0
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1
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1
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Step 5: Finally, fill in all of the blank
columns with 0s. The completed binary number is:
11000011
Here are some more examples. Try the method above
to test if they are correct.
• 198 = 11000110
• 118 = 1110110
• 529 = 1000010001
• 991 = 1111011111
Finally, here is a javascript code to convert numbers
from base 10 into binary. 
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