X+53896=54123 x-235689=125682 x*36=7956 x:13=21
1)х+53896=54123 х=54123-53896 х=227 2)х-235689=125682 х=125682+235689 х=361371 3)х*36=7956 х=7956:36 х=221 4)х:13=21 х=21*13 х=273