Can anyone tell me why 'denn' is used in one of the sentences below and 'dann' is used in the other?  I had read that 'denn'  is equivalent to 'then' in English while 'dann' was equivalent to 'than' but 'then' would seem to be the correct English translation in both of the sentences below.

Dort machen wir dann unsere Hochzeitsfotos.
Wie kommen wir denn vom Rathaus zum Schlosspark?
 

Hi Byron,

'Dann' and 'denn' are quite similar but not always exchangeable with each other. ​
'Bis dann!' / 'Bis denn!' ='See you then!'
'Dann' gives a vage time reference meaning then, afterwards 'denn' meaning 'than, for ' and used as another form of 'weil'= 'because' but grammatically not in the same way. 'Ich bin hungrig, denn ich habe nichts gegessen' / 'Ich bin hungrig, weil ich nichts gegessen habe' = 'I am hungry because I have not eaten. '
Depending on the context 'dann' can also mean 'if..then'. 
'Wenn das so ist, dann weiss ich auch nicht.' = 'If so, then I don't know.'
'Dann weiss ich auch nicht' = 'If so, I don't know'.

'Denn' is often used as a filler. In this example 'denn' softens the question, which would sound harsh otherwise. "was denn?" instead "was?"

Er: "Ach, Mist!" = He: " Oh, crap! " 
Sie: "Was denn?" =  She : "What? "
Er:"Ich hab es zerbrochen" = He: " I've broken it "

Regards

Paul

 

Thanks Paul.  That helps.  I had noticed that 'denn' is often used as filler and isn't even included in the translation.  That's commonly done too in certain regions of the U.S. particularly the upper midwest.which includes Minnesota, North Dakota, and Wisconsin.  If you've watched the movie Fargo, you've seen examples of that although the dialect, while authentic, is just a little bit over the top.

regards,

Byron