decimal to binary (idea)

So you want to convert a number (decimal) into binary, do you now? Here's the pencil and paper method us old farts got taught back when the Earth was still young. As an example, we'll convert 163 to binary as we go along.

Take your number and repeatedly divide by 2 (until you reach 1, when there's really not much point in going on (but you can!)). Ignore any remainders (we'll come back later to pick them up).

163
81
40
20
10
5
2
1

Now read the column of numbers from the bottom up; write down (from left to right!) a "1" for every odd number, a "0" for every even number.

In our case, this yields 10100011₂=163₁₀.