why the symbolic vector minus a scalar vector produce a vector with fraction?

[Sacaq]

Hi~

When I try to solve some equations, I found the solution was all fractions.
check the value of each vector, I found where the situation start.
The codes are like this:

A12=[5.5,398,455]
syms a b c
A=[a,b,c]
AA12=A12-A

and the output were:

A12 =
5.5000 398.0000 455.0000

A =
[ a, b, c]

AA12 =
[ 11/2 - a, 398 - b, 455 - c]

After I use the function "solve" to solve the equations, the solution matrix is full of fractions.

 

[Sacaq]

OK, I found a solution.
just like this:

A=double(A)

It seems the glitch is the format.