A numeric-control work centre for machining plates of stone, marble, or, in general, natural or synthetic stone material, or ceramic material, comprising: - a work surface; and - at least one working head movable on the work surface in at least two mutually orthogonal horizontal directions (X,Y), wherein said working head can be coupled either to a tool for performing grinding or milling machining operations on the plate or to a tool for cutting the plate, wherein said work surface includes: - a rigid supporting board, defining a first planar supporting surface; and - a series of elements (131, 132) for supporting a plate during a cutting operation, said elements (131, 132) being rigidly connected to said rigid supporting board and defining a second supporting surface located at a higher level than said first planar supporting surface of said supporting board, so that a cutting tool coupled to said at least one working head can carry out a cutting operation on a plate arranged on said elements (131, 132) for supporting the plate, without interfering with the supporting board, said machine including a third supporting surface located at a higher level than said second supporting surface, and adapted for supporting and holding a plate during a grinding or milling operation performed on the plate by a tool coupled to said working head and suitable for performing grinding or milling machining operations on the plate, wherein - said elements (131, 132) for supporting the plate during a cutting operation are rigid sacrificial elements secured to the work surface and made of a sacrificial material, such as wood or the like, such that a cutting tool used in the cutting operation can pass through the plate and also engrave the sacrificial elements, without interfering with the work surface of the machine, so that the cutting tool can be guided according to any path on the work surface, without being forced to avoid interference with said sacrificial elements (131, 132); characterised by - said third supporting surface is defined by a plurality of supporting blocks, each of which has a bottom suction cup that can be selectively activated for adhering to said work surface and a top suction cup that can be selectively activated for holding thereon a plate to be subjected to a milling or grinding operation; - defined between the sacrificial elements (131, 132) are free portions of said first planar surface of the supporting board, which are confined between said sacrificial elements and distributed throughout the entire extension of said first surface so that they can be used for removably engaging said supporting blocks thereon; and - in the condition where said supporting blocks are engaged on respective free portions of the work surface, the top suction cups of the supporting blocks project above said sacrificial elements (131, 132) and define said third supporting surface. - a work surface; and - at least one working head movable on the work surface in at least two mutually orthogonal horizontal directions (X,Y), wherein said working head can be coupled either to a tool for performing grinding or milling machining operations on the plate or to a tool for cutting the plate, - a rigid supporting board, defining a first planar supporting surface; and - a series of elements (131, 132) for supporting a plate during a cutting operation, said elements (131, 132) being rigidly connected to said rigid supporting board and defining a second supporting surface located at a higher level than said first planar supporting surface of said supporting board, so that a cutting tool coupled to said at least one working head can carry out a cutting operation on a plate arranged on said elements (131, 132) for supporting the plate, without interfering with the supporting board, - said elements (131, 132) for supporting the plate during a cutting operation are rigid sacrificial elements secured to the work surface and made of a sacrificial material, such as wood or the like, such that a cutting tool used in the cutting operation can pass through the plate and also engrave the sacrificial elements, without interfering with the work surface of the machine, so that the cutting tool can be guided according to any path on the work surface, without being forced to avoid interference with said sacrificial elements (131, 132); characterised by - said third supporting surface is defined by a plurality of supporting blocks, each of which has a bottom suction cup that can be selectively activated for adhering to said work surface and a top suction cup that can be selectively activated for holding thereon a plate to be subjected to a milling or grinding operation; - defined between the sacrificial elements (131, 132) are free portions of said first planar surface of the supporting board, which are confined between said sacrificial elements and distributed throughout the entire extension of said first surface so that they can be used for removably engaging said supporting blocks thereon; and - in the condition where said supporting blocks are engaged on respective free portions of the work surface, the top suction cups of the supporting blocks project above said sacrificial elements (131, 132) and define said third supporting surface.