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计算(0.1+0.12+0.123+0.1234)×(0.12+0.123+0.1234+0.12345)-(0.1+0.12+0.123+0.1234+0.12345)×(计算(0.1+0.12+0.123+0.1234)×(0.12+0.123+0.1234+0.12345)-(0.1+0.12+0.123+0.1234+0.12345)×(0.12+0.123+0.1234)

题目详情
计算(0.1+0.12+0.123+0.1234)×(0.12+0.123+0.1234+0.12345)-(0.1+0.12+0.123+0.1234+0.12345)×(
计算
(0.1+0.12+0.123+0.1234)×(0.12+0.123+0.1234+0.12345)-(0.1+0.12+0.123+0.1234+0.12345)×(0.12+0.123+0.1234)

▼优质解答
答案和解析
设(0.1+0.12+0.123+0.1234)=A,(0.12+0.123+0.1234)=B,则A-B=0.1,
(0.1+0.12+0.123+0.1234)×(0.12+0.123+0.1234+0.12345)-(0.1+0.12+0.123+0.1234+0.12345)×(0.12+0.123+0.1234)
=A×(B+0.12345)-(A+0.12345)×B
=AB+0.12345A-(AB+0.12345B)
=AB+0.12345A-AB-0.12345B
=0.12345×(A-B)
=0.12345×0.1
=0.012345.