circuits parallel and series

First question - in a closed circuit does the voltage change across resistors? for example. If you start with 20 volts what is the voltage across the resistor/

Second question - does current change across resistors? If you have a closed circuit with one resistor (R1) then two resistors in parallel (R2, R3), is the current passing through R3 just I = V/R3 or I= V/Rtotal?

Thank you very much!

1) In resistor parallel circuits , voltage doesn't change; In resistor series circuits VRx = Vt * Rx / Rtotal

2) In resistor parallel circuits current across a resistor doesn't change; In resistor series circuits Itotal = Vtotal/Rtotal

Your questions are rather vague.

In the title you wrote "circuits in paralle and series" but there is no mention of "series" in the questions.

I suggest that you post a circuit so we can see what you are trying to do.

A picture is worth a 1000 words.

oops