Đáp án:
$B=\dfrac{445}{246}$
Giải thích các bước giải:
$B=\dfrac{5}{13}+\dfrac{5}{6}+\dfrac{-21}{41}+\dfrac{8}{13}+\dfrac{20}{41}$
$B=\Big(\dfrac{5}{13}+\dfrac{8}{13}\Big)+\Big(\dfrac{-21}{41}+\dfrac{20}{41}\Big )+\dfrac{5}{6}$
$B=\Big(\dfrac{13}{13}\Big)+(\dfrac{-1}{41})+\dfrac{5}{6}$
$B=\dfrac{41-1}{41}+\dfrac{5}{6}$
$B=\dfrac{40}{41}+\dfrac{5}{6}$
$B=\dfrac{40.6+41.5}{246}$
$B=\dfrac{445}{246}$