Question

Tính

A = 1.2.3...8.9 - 1.2.3...7.8 - 1.2.3...8.8

Answer 1

\(A=1.2.3.4...8.9-1.2.3.4...7.8-1.2.3...8.8\)

\(A=1.2.3...8.\left(9-1-8\right)\)

\(A=1.2.3...8.9.0\)

\(A=0\)

Vậy \(A=0\)

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