modeller:
retrolefty:
As the teacher once told you in school, you must show your work! Blowing up is like saying your dog eat your homework.You want a picture of my HP calculator display?
If I attempt the first 1/R1 it says Divide by Zero error.
That was simply a user input error, as there are no zero ohm resistor, certainly not a room temperature. Put in the real resistance values and it will work. 
Lefty