  We present relativistic coupled-cluster (CC) calculations of energies,
magnetic-dipole hyperfine constants, and electric-dipole transition amplitudes
for low-lying states of atomic boron. The trivalent boron atom is
computationally treated as a monovalent system. We explore performance of the
CC method at various approximations. Our most complete treatment involves
singles, doubles and the leading valence triples. The calculations are done
using several approximations in the coupled-cluster (CC) method. The results
are within 0.2-0.4% of the energy benchmarks. The hyperfine constants are
reproduced with 1-2% accuracy.
