# Easy way to draw truth tables?

1. Dec 10, 2015

### DiamondV

1. The problem statement, all variables and given/known data
So, in a lot of the questions in exams, I am asked to draw truth tables which are followed up by K maps, usually these truth tables have like 4 variables, now my issue is, is there any easy to draw them, like I cant seem to get my head around writing out all the possible combinations, i just confused. I usually start with one variable being 1 rest 0, but i dont where to keep going? I have no structure.

2. Relevant equations

3. The attempt at a solution

2. Dec 10, 2015

### RUber

I normally start with one column at a time.
Since you have 2 options for each one, you will need 2^k rows for k variables.
For the first column (variable) make the first half of the rows 1 and the second half 0. Then move to the next column and do 1/2 and 1/2, and so on...
Ex:
$\begin{matrix} 1&1&1\\1&1&0\\1&0&1\\1&0&0\\0&1&1\\0&1&0\\0&0&1\\0&0&0\end{matrix}$

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