Đáp án:
Ta có:
$A = \underbrace{3333.........3333}_{50 c/s 3} . \underbrace{999.......999}_{50 c/s 9}$
$A = \underbrace{3333.........3333}_{50 c/s 3} . (\underbrace{1000........000}_{50 c/s 0} - 1)$
$A = \underbrace{3333.........3333}_{50 c/s 3} . \underbrace{1000........000}_{50 c/s 0} - \underbrace{3333.........3333}_{50 c/s 3}$
$A = \underbrace{3333.......3333000.........0000}_{50 c/s 3; 50 c/s 0} - \underbrace{3333.........3333}_{50 c/s 3}$
$A = \underbrace{333333........33332666.........6667}_{49 c/s 3; 1 c/s 2; 49 c/s 0; 1 c/s 7}$
