$1)$
$A=\dfrac{55}{11.16}+\dfrac{55}{16.21}+\dfrac{55}{21.26}+\dfrac{55}{26.31}+\dfrac{55}{31.36}+\dfrac{55}{36.41}$
$A=11(\dfrac{5}{11.16}+\dfrac{5}{16.21}+\dfrac{5}{21.26}+\dfrac{5}{26.31}+\dfrac{5}{31.36}+\dfrac{5}{36.41})$
$A=11(\dfrac{1}{11}-\dfrac{1}{16}+\dfrac{1}{16}-\dfrac{1}{21}+\dfrac{1}{21}-\dfrac{1}{26}+\dfrac{1}{26}-\dfrac{1}{31}+\dfrac{1}{36}-\dfrac{1}{41})$
$A=11(\dfrac{1}{11}-\dfrac{1}{41})$
$A=11(\dfrac{41}{451} -\dfrac{11}{451})$
$A=\dfrac{30}{451}$
$A=\dfrac{30}{41}$
$------$
$2)$
$\dfrac{1}{3}=\dfrac{3}{9}$
$\dfrac{6:(3-2).2}{6:(3-2).9} =\dfrac{12}{54}$
$------$
$\text{CHO MK CÂU TRẢ LỜI HAY NHẤT NHA!!}$
