Is my Req correct? (very simple electronics question)

[Femme_physics]

I just need to find the Req of the circuit. Everything is attached. Ignore the fact there's no R4.

Is it correct?

 

[da_nang]

Your symbolic calculations are correct, yes. You have, however, added 100 Ohm too much in R_1,2.

 

[Femme_physics]

Ah, thank you for catching my thoughtless error :) unless anyone makes another reply I'm going to assume other than that it's all correct