EntityQ668804· pop 5· linked from 19 articlesCovering systemSign in to savecollection of finitely many residue classes whose union contains every integerConnectionsmodular arithmeticEntitymathematicsEntityInternational Standard Book NumberEntityWayback MachineEntitydigital object identifierEntityPDFEntityPaul ErdősEntityparityEntitycomposite numberEntityJSTOREntityQ118398EntitycoprimeEntityChinese remainder theoremEntityFibonacci sequenceEntityOn-Line Encyclopedia of Integer SequencesEntityrecurrence relationEntitylist of unsolved problems in mathematicsEntityMathematical ReviewsEntityAnnals of MathematicsEntityRichard RadoEntityCategoriesUnsolved problems in number theory