TÍNH NHANH: a) -3/7+15/26- ( 2/13- 3/7) b) 2 23/7 = ( 2/9- 1 3/7 ) – -5/3 : 1/9 05/12/2021 Bởi Samantha TÍNH NHANH: a) -3/7+15/26- ( 2/13- 3/7) b) 2 23/7 = ( 2/9- 1 3/7 ) – -5/3 : 1/9
a, $\dfrac{-3}{7}+\dfrac{15}{26}-(\dfrac{2}{13}-\dfrac{3}{7})$ $=\dfrac{-3}{7}+\dfrac{15}{26}-\dfrac{2}{13}+\dfrac{3}{7}$ $=\dfrac{-3}{7}+\dfrac{3}{7}+\dfrac{15}{26}-\dfrac{2}{13}$ $=\dfrac{15}{26}-\dfrac{4}{26}$ $=\dfrac{11}{26}$ b, $2\dfrac{23}{7}+(\dfrac{2}{9}-1\dfrac{3}{7})-\dfrac{-5}{3}:\dfrac{1}{9}$ (dấu = mình thay bằng dấu +) $=\dfrac{37}{7}+\dfrac{2}{9}-\dfrac{10}{7}+\dfrac{5}{3}\cdot9$ $=\dfrac{37}{7}-\dfrac{10}{7}+\dfrac{2}{9}+15$ $=\dfrac{27}{7}+\dfrac{137}{9}$ $=\dfrac{1202}{63}$ Bình luận
`a,(-3)/7+15/26-(2/13 – 3/7)` `=(-3)/7 + 15/26 – 2/13 + 3/7` `=[(-3)/7 + 3/7] +15/26 – 4/26` `=0+ 11/26` `b,2 23/7 + (2/9 – 1 3/7) – (-5)/3 : 1/9` `=37/7 + (2/9 – 10/7 ) – (-5)/3 : 1/9` `=37/7 + 2/9 -10/7 – (-5)/3 .9` `=37/7 +2/9 -10/7 -(-15)` `=347/63 -10/7 +15` `=257/63 +15` `=1202/63` ~ Học tốt ~ Bình luận
a, $\dfrac{-3}{7}+\dfrac{15}{26}-(\dfrac{2}{13}-\dfrac{3}{7})$
$=\dfrac{-3}{7}+\dfrac{15}{26}-\dfrac{2}{13}+\dfrac{3}{7}$
$=\dfrac{-3}{7}+\dfrac{3}{7}+\dfrac{15}{26}-\dfrac{2}{13}$
$=\dfrac{15}{26}-\dfrac{4}{26}$
$=\dfrac{11}{26}$
b, $2\dfrac{23}{7}+(\dfrac{2}{9}-1\dfrac{3}{7})-\dfrac{-5}{3}:\dfrac{1}{9}$ (dấu = mình thay bằng dấu +)
$=\dfrac{37}{7}+\dfrac{2}{9}-\dfrac{10}{7}+\dfrac{5}{3}\cdot9$
$=\dfrac{37}{7}-\dfrac{10}{7}+\dfrac{2}{9}+15$
$=\dfrac{27}{7}+\dfrac{137}{9}$
$=\dfrac{1202}{63}$
`a,(-3)/7+15/26-(2/13 – 3/7)`
`=(-3)/7 + 15/26 – 2/13 + 3/7`
`=[(-3)/7 + 3/7] +15/26 – 4/26`
`=0+ 11/26`
`b,2 23/7 + (2/9 – 1 3/7) – (-5)/3 : 1/9`
`=37/7 + (2/9 – 10/7 ) – (-5)/3 : 1/9`
`=37/7 + 2/9 -10/7 – (-5)/3 .9`
`=37/7 +2/9 -10/7 -(-15)`
`=347/63 -10/7 +15`
`=257/63 +15`
`=1202/63`
~ Học tốt ~