用简便方法计算下面各题 1. 66*21+19*21+85*19 2. 36*111+888*8 99*99+199
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解:1: 66×21+19×21+85×19
=(66+19)×21+85×19
=85×21+85×19
=85×(21+悄棚带19)
=85×40
=3400
2: 36×111+和冲888×8
=36×111+111×64
=(36×64)×111
=11100
3: 99×99+启芦199
=99×99+99+100
=99×(99+1)+100
=99×100+100
=(99+1)×100
=100×100
=10000
=(66+19)×21+85×19
=85×21+85×19
=85×(21+悄棚带19)
=85×40
=3400
2: 36×111+和冲888×8
=36×111+111×64
=(36×64)×111
=11100
3: 99×99+启芦199
=99×99+99+100
=99×(99+1)+100
=99×100+100
=(99+1)×100
=100×100
=10000
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