Yes and no. The number 0.50 has no dimension. You would want 0.50 mile. However, that still presents another problem. Expressing the distance to two decimal places implies accuracy to the nearest 0.01 mile, while the expression "half a mile" suggests a much looser standard.
Answers & Comments
One half = ¹/₂ = .5 = 0.5 = .50 = 0.50
Yes, and 0.50 is the same as 0.5
1/2 mile = 0.5 mile
Yes and no. The number 0.50 has no dimension. You would want 0.50 mile. However, that still presents another problem. Expressing the distance to two decimal places implies accuracy to the nearest 0.01 mile, while the expression "half a mile" suggests a much looser standard.
1/2 = 0.50 regardless of the unit
1/2 mile = 0.5 mile
Just .5 of a mile. Some people would say .5 miles, but less than 1 would be a singular mile.