\(A=\frac{-2}{17}+\frac{15}{23}+\frac{-15}{17}+\frac{4}{19}+\frac{8}{23}\)
\(=\left(\frac{-2}{17}+\frac{-15}{17}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\)
\(=\frac{-17}{17}+\frac{23}{23}+\frac{4}{9}\)
\(=-1+1+\frac{4}{9}=0+\frac{4}{9}=\frac{4}{9}\)
#Hoq chắc _ Baccanngon
tính hợp lí :(8/23+3/19-15/17)-(2/17-15/23)
tính hợp lí :(8/23+3/19-15/17)-(2/17-15/23)
f\(\dfrac{-2}{17}+\dfrac{15}{23}+\dfrac{-15}{17}+\dfrac{4}{19}+\dfrac{8}{23}\)
g \(\dfrac{-1}{2}+\dfrac{3}{21}+\dfrac{-2}{6}+\dfrac{-5}{30}\)
bài 1
a. 5/18 + 8/19 - 7/21 + ( -10/36 + 11/19 + 1/3) - 5/8
b.1/13 + ( -5/18 - 1/13 + 12/17 ) - ( 12/17 - 5/18 + 7/5 )
c.15/14 - (17/23 - 80/87 + 5/4)+(17/23 - 15/14 + 1/4 )
d.1/25 - 4/27 + ( -23/27 + -1/25 - 5/43 ) + 5/43 - 4/7
bài 2
a. x +1/3 = 3/4
b. x - 2/5 = 5/7
c. -x - 2/3 = -6/7
d. 4/7 - x = 1/3
e. x+ 5/2 = -3/2
f. x + 5/6 = -1/12
GIÚP MÌNH VỚI Ạ MÌNH CẢM ƠN TRƯỚC
A=15/19 . 17/23 + 15/19 . 19/23 - 15/19 . 13/23 = ?
a 12 – 34 b 23 – 47 c 31 – 23 d 9 – 5 e 4 – 15 25 f 23 13 17 57 g 4 . 9 6 . 12 – 7 h 14 6 19 14 19 i 56 – 8. 27 7 j 8 5 . 2 – 3 6 k 4 . 3 125 . 25 8 l 9 6 . 3 – 4 7 m 45. 18 – 15 – 18. 45 – 15
A=15/19 . 17/23 + 15/29 . 19/23 - 15/19 . 13/23
B , Tìm các chữ số a,b để : 4a67b chia hết cho 2 ; 5 và 9
tinh nhanh
3) (187 -23) – (20 – 180)
4) (-37 – 17). (-9) + 35. (-9 – 11)
5) (-50 +19 +143) – (-79 + 25 + 48)
6) (-8).25.(-2). 4. (-5).125
7) 3784 + 23 – 3785 – 15
