The quantum Euclidean spheres, S q , are (noncommutative) homogeneous spaces of quantum orthogonal groups, SOq(N). The ∗-algebra A(S q ) of polynomial functions on each of these is given by generators and relations which can be expressed in terms of a self-adjoint, unipotent matrix. We explicitly construct complete sets of generators for the K-theory (by nontrivial self-adjoint idempotents and ...