# Logic Gates for Boolean Algebra

Hi, @jbyers @bryanray @Rafi I am working on the practice test #2 and I am getting confused with the logic gates even with me watching the videos. So here is a screenshot of my dilemma……

so I am trying to understand where the values are coming from in the logic gate.The
w=1
x=1
y=1
z=0

Where did those values come from because I came up with:
w’z+x’z’
1(1)+1(1)
w=1
x=1
y=0 (because it’s not used in this expression)
z=1

so how do I derive the numbers to begin putting the input into the Logic Gate?
Thank you guys so much for your help.

Hey Khalif!

The numbers for each variable on the left side of the logic gate simply represent all possible inputs for each variable. The number on the right side of the logic gate represents what the output is for the supplied inputs. So for example with the above logic gate when we have

w = 1
x = 1
y = 1
z = 0

the output of the logic gate would be 0. If you look at the k map that the expression (and logic gate) are derived from, you will see that the minterm for those values of the variables is 0. If you were to take any other possible inputs from the k map and plug them in the logic gate, you’ll see that the output from the logic gate matches up with the minterm from the kmap.

Thank you @brendankane however me being the investigative person that I am am still trying to understand where those number 1’s are coming from. Like why couldn’t they be 0s instead? How was it determined that w,x,y =1 and z=0? Also you mentioned the minterm, however I don’t recall that being explained in detail throughout the coursework and I am still confused on what a minterm even is. Thank You again for your time. It is greatly appreciated.

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Actually thank you @brendankane I just found a YouTube video explaining the minterms and how to find them. Anyone wishing to view it the link is below

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