\(A=1.2.3......100-1.2.3....99-1.2.3....99^2\)
\(=1.2.3...99\left(100-1-99\right)\)
\(=0\)
Bài làm :
Ta có :
\(A=1.2.3...100-1.2.3...99-1.2.3...99^2\)
\(A=\left(1.2.3...99\right)\left(100-1-99\right)\)
\(A=\left(1.2.3...99\right).0\)
\(A=0\)
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