计算.(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.
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计算.
(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234+1.2345)×(1.2+1.23+1.234)
(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234+1.2345)×(1.2+1.23+1.234)
![计算.(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.](/uploads/image/z/8316904-40-4.jpg?t=%E8%AE%A1%E7%AE%97%EF%BC%8E%EF%BC%881%2B1.2%2B1.23%2B1.234%EF%BC%89%C3%97%EF%BC%881.2%2B1.23%2B1.234%2B1.2345%EF%BC%89-%EF%BC%881%2B1.2%2B1.23%2B1.)
设1+1.2+1.23+1.234=a,1+1.2+1.23+1.234+1.2345=b,则:
(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234+1.2345)×(1.2+1.23+1.234),
=a×(b-1)-b×(a-1),
=ab-a-ab+b,
=b-a,
=(1+1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234),
=1.2345.
(1+1.2+1.23+1.234)×(1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234+1.2345)×(1.2+1.23+1.234),
=a×(b-1)-b×(a-1),
=ab-a-ab+b,
=b-a,
=(1+1.2+1.23+1.234+1.2345)-(1+1.2+1.23+1.234),
=1.2345.