How to evaluate current in a circuit involving short circuit?
You've worked it out on your own. Congratulations. Here's how I would have approached it.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. The original. Note that R2 is short-circuited. It can be removed.







simulate this circuit

Figure 2. Note that R3 and R4 are in parallel.







simulate this circuit

Figure 3. Now we can add the series resistances.







simulate this circuit

Figure 4. This is as far as we need to go.

You can apply your current division here.