How is the starting point determined when calculating sum voltage in a series?

[fran1942]

Hello, we have been told the sum voltage in this circuit is +2V -6V +4V +3V = 3V.

I was just wondering why the 2V was the starting point for this calculation because if you start from any of the other point, the end result is different.

Is there a rule as for where you start your calculation from, when working out sum voltage in a series ?

Thanks kindly for any help.

 

[vk6kro]

It doesn't matter where you start from.

There are 3 batteries facing one way and one facing the other way. So, you add up the 3 (to get 9 volts) and take away the other one to get 3 volts.