  In this article, we establish a motivic analog of an enumeration result of
James-Thomas on non-stable vector bundles in topological setting. Using this,
we obtain results on enumeration of projective modules of rank $d$ over a
smooth affine $k$-algebra $A$ of dimension $d$, recovering in particular
results of Suslin and Bhatwadekar on cancellation of such vector bundles.
Admitting a conjecture of Asok and Fasel, we prove cancellation of such vector
bundles of rank $d-1$ if the base field $k$ is algebraically closed. We also
explore the cancellation properties of symplectic vector bundles.
