20022003×20032002-2002002×20032003=(20022002+1)×(20032003-1)-20022002×20032003 可令A=20022002,B=20032003原式=(A+1)(B-1)-AB =AB-A+B-1-AB =B-A=1 =20032003-20022002-1 =10001-1 =10000