James run 12 3/4 miles per day. he runs for 6 days the same amount of miles each day. how many miles does he run in all?

The answer is:  76.5 mi. (or, write as: 76 ½ mi. ). 

Explanation:

(12 ¾ mi / d) * 6 d =  ?  mi.

 On the "left-hand side" of the equation, the units of "d" [for day(s)] cancel; and we are left with: 

12 ¾ mi * 6  =  ?  mi.   ;

12 ¾ mi * 6  = (12 ¾ * 6) mi.  = 76.5 mi. (or, write as: 76 ½ mi. ).