  The multiplicity and elliptic flow of charged particles produced in Pb-Pb
collisions at center of mass energy $\sqrt{s_{NN}}=2.76$ TeV from the Large
Hadron Collider are studied in a multiphase transport (AMPT) model. With the
standard parameters in the HIJING model, which is used as initial conditions
for subsequent partonic and hadronic scatterings in the AMPT model, the
resulting multiplicity of final charged particles at mid-pseudorapidity is
consistent with the experimental data measured by the ALICE Collaboration. This
value is, however, increased by about 25% if the final-state partonic and
hadronic scatterings are turned off. Because of final-state scatterings,
particular those among partons, the final elliptic flow of charged hadrons is
also consistent with the ALICE data if a smaller but more isotropic parton
scattering cross section than previously used in the AMPT model for describing
the charged hadron elliptic flow in heavy ion collisions at the Relativistic
Heavy Ion Collider is used. The resulting transverse momentum spectra of
charged particles as well as the centrality dependence of their multiplicity
density and the elliptic flow are also in reasonable agreement with the ALICE
data. Furthermore, the multiplicities, transverse momentum spectra and elliptic
flows of identified hadrons such as protons, kaons and pions are predicted.
