一、编写一个操作父类 usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespace多态计算器 {//////计算父类///classOperation {publicintNumA {get;set; }publicintNumB {get;set; }publicOperation(intnumA,intnumB) {this.NumA =numA;this.NumB =...