Quantum　error　correction　(QEC)　aims　to　protect　logical　qubits　from　noises　by　using　the　redundancy　of　a　large　Hilbert　space,　which　allows　errors　to　be　detected　and　corrected　in　real　time(1).　In　most　QEC　codes(2-8),　a　logical　qubit　is　encoded　in　some　discrete　variables,　for　example　photon　numbers,　so　that　the　encoded　quantum　information　can　be　unambiguously　extracted　after　processing.　Over　the　past　decade,　repetitive　QEC　has　been　demonstrated　with　various　discrete-variable-encoded　scenarios(9-17).　However,　extending　the　lifetimes　of　thus-encoded　logical　qubits　beyond　the　best　available　physical　qubit　still　remains　elusive,　which　represents　a　break-even　point　for　judging　the　practical　usefulness　of　QEC.　Here　we　demonstrate　a　QEC　procedure　in　a　circuit　quantum　electrodynamics　architecture(18),　where　the　logical　qubit　is　binomially　encoded　in　photon-number　states　of　a　microwave　cavity(8),　dispersively　coupled　to　an　auxiliary　superconducting　qubit.　By　applying　a　pulse　featuring　a　tailored　frequency　comb　to　the　auxiliary　qubit,　we　can　repetitively　extract　the　error　syndrome　with　high　fidelity　and　perform　error　correction　with　feedback　control　accordingly,　thereby　exceeding　the　break-even　point　by　about　16%　lifetime　enhancement.　Our　work　illustrates　the　potential　of　hardware-efficient　discrete-variable　encodings　for　fault-tolerant　quantum　computation(19).