Yes.
The decimal 0.5 can be represented as a fraction of 5/10, which simplifies to 1/2.
0.5 is half of 1, as is 1/2.
When you multiply either 0.5 or 1/2 by 2, you get 1.
So when you add 0.5 or 1/2 to the same base number, they both equal the same thing.
3.5 does equal 3 ½
Hope this helps!