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Converting Decimal to Binary
Converting from Decimal to Binary is a little bit harder than going the other way. If you follow the steps you will have no problems.
To change from Decimal to Binary you carry out a series of subtractions based on the Binary 'Place' values...
Binary Place Values 
D7 
D6 
D5 
D4 
D3 
D2 
D1 
D0 
128 
64 
32 
16 
8 
4 
2 
1 
Consider decimal 150...
Step 1 Subtract 128 150  128 = 22
Since 150 'contained' 128, D7 is "1". The binary number so far is: 1 X X X X X X X
Step 2 Subtract 64 from 22 Can't. D6 is zero. The binary number so far is: 1 0 X X X X X X
Step 3 Subtract 32 fom 22 Can't. D5 is zero. The binary number so far is: 1 0 0 X X X X X
Step 4 Subtract 16 22  16 = 6
Since 150 'contained' 16, D4 is "1". The binary number so far is: 1 0 0 1 X X X X
Step 5 Subtract 8 from 6 Can't. D3 is zero. The binary number so far is: 1 0 0 1 0 X X X
Step 6 Subtract 4 from 6 6  4 = 2
Since 150 'contained' 4, D2 is "1".The binary number so far is: 1 0 0 1 0 1 X X
Step 7 Subtract 2 from 2 2  2 = 0
Since 150 'contained' 2, D1 is "1". The binary number so far is: 1 0 0 1 0 1 1 X
NOTE: You need to be careful you don't write down zero at this point.
Step 8 Subtract 1 from 0 Can't. D0 is zero. The binary number is: 1 0 0 1 0 1 1 0
i.e.
150 decimal is 10010110 binary.
Decimal to Binary Conversion Table
Decimal Number 
Place Value 

Balance 
Binary Number ("X" = unknown) 
150 
 128 
OK 
= 
22 
1 
X 
X 
X 
X 
X 
X 
X 
22 
 64 
can't 
= 
22 
1 
0 
X 
X 
X 
X 
X 
X 
22 
 32 
can't 
= 
22 
1 
0 
0 
X 
X 
X 
X 
X 
22 
 16 
OK 
= 
6 
1 
0 
0 
1 
X 
X 
X 
X 
6 
 8 
can't 
= 
6 
1 
0 
0 
1 
0 
X 
X 
X 
6 
 4 
OK 
= 
2 
1 
0 
0 
1 
0 
1 
X 
X 
2 
 2 
OK 
= 
0 
1 
0 
0 
1 
0 
1 
1 
X 
0 
 1 
can't 
= 
0 
1 
0 
0 
1 
0 
1 
1 
0 

i.e. Decimal 150 = Binary 10010110 
You should check your answer by doing a Binary to Decimal conversion...
10010110 = 128 + 0 + 0 + 16 + 0 + 4 + 2 + 0 = 150
Open the worksheet table above in Word format
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