There is no present division in a series link. All of the resistors have the same current flowing through them.

Ohm’s law is used to compute the amount of current flowing across the resistors.

But first, let’s figure out what the comparable resistance is:

R = 0.2 + 0.3 + 0.4 + 0.5 + 12 = 13.4 

Using Ohm’s law as a guide,

0.671 A is the current flowing over the 12.