几道数学题,(简便方法)
654321X123456-654322X123455
8642X2468-8644X2466
2002X60066006-3003X40044004
1234X432143214321-4321X123412341234
50X96+57X4+7X66
9999X1222-3333X666
1989X1999-1988X2000
7654321X124567-77654322X1234566