Tính nhanh
B= $\frac{5}{13}$ + $\frac{5}{6}$ + $\frac{-21}{41}$ + $\frac{8}{13}$ + $\frac{20}{41}$
Tính nhanh B= $\frac{5}{13}$ + $\frac{5}{6}$ + $\frac{-21}{41}$ + $\frac{8}{13}$ + $\frac{20}{41}$
By Eliza
By Eliza
Tính nhanh
B= $\frac{5}{13}$ + $\frac{5}{6}$ + $\frac{-21}{41}$ + $\frac{8}{13}$ + $\frac{20}{41}$
Đáp án:
$B=\dfrac{445}{246}$
Giải thích các bước giải:
$B=\dfrac{5}{13}+\dfrac{5}{6}+\dfrac{-21}{41}+\dfrac{8}{13}+\dfrac{20}{41}$
$B=\Big(\dfrac{5}{13}+\dfrac{8}{13}\Big)+\Big(\dfrac{-21}{41}+\dfrac{20}{41}\Big )+\dfrac{5}{6}$
$B=\Big(\dfrac{13}{13}\Big)+(\dfrac{-1}{41})+\dfrac{5}{6}$
$B=\dfrac{41-1}{41}+\dfrac{5}{6}$
$B=\dfrac{40}{41}+\dfrac{5}{6}$
$B=\dfrac{40.6+41.5}{246}$
$B=\dfrac{445}{246}$
Đáp án:
`405/246`
Giải thích các bước giải:
`5/13+5/6+(-21)/41+8/13+20/41`
`=(5/13+8/13)+((-21)/41+20/41)+5/6`
`=13/13+(-1)/41+5/6`
`=1+(-1)/41+5/6`
`=(41-1)/41+5/6=40/41+5/6`
`=(40xx5+5xx41)/(41xx6)=405/246`