Tính 5/19.8/11-5/19.2/11-5/19:1/11+14/19
a,(-25) .125.4.(-8) .(-17)
b,-3\4+2\7+-1\4+3\5+5\7
c,7\19.8\11+7\19.3\11-12\19
d,19 5\8:7\2013-26 5\8:7\2013
e,-5\12.2\11+-5\12.9\11+5\12
a) (- 25) x 125,4 x (-8) x (-17)
= (- 25 x 4) x (- 8 x 125) x (-17)
= (-100) x (-1000) x (-17)
= - 1 700 000
b) \(\frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{3}{5}+\frac{5}{7}\)
\(=\left(\frac{-3}{4}+\frac{-1}{4}\right)+\left(\frac{2}{7}+\frac{5}{7}\right)+\frac{3}{5}\)
\(=-1+1+\frac{3}{5}\)
\(=0+\frac{3}{5}=\frac{3}{5}\)
c) \(\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.\frac{3}{11}-\frac{12}{19}\)
\(=\frac{7}{19}.\left(\frac{8}{11}+\frac{3}{11}\right)-\frac{12}{19}\)
\(=\frac{7}{19}.1-\frac{12}{19}\)
\(=\frac{7}{19}-\frac{12}{19}=\frac{-5}{19}\)
d) \(19\frac{5}{8}:\frac{7}{2013}-26\frac{5}{8}:\frac{7}{2013}\)
\(=\left(19\frac{5}{8}-26\frac{5}{8}\right):\frac{7}{2013}\)
\(=-7:\frac{7}{2013}\)
\(=-2013\)
e) \(\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}\)
\(=\frac{-5}{12}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{5}{12}\)
\(=\frac{-5}{12}.1+\frac{5}{12}\)
\(=\frac{-5}{12}+\frac{5}{12}=0\)
~Học tốt~
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
4) so sánh hai phân số sau
a) 7/15 và 4/9
B1 tính nhanh nếu có thể
a) (-18).5+5.10+5.(-2)
b) (-15):(-5)+7.(-3/7)
c) (-157)+(-16)+257+(-43)+(-84)
d) (+23)+(-135)-(-77)-/-65/+(-30)
e) -5/7 + (-6/11+1)
f) 1/2-2/3+4/5-5/6
g)1/3.4/5+1/3.6/5+2/3
h) -5/7.2/11+-5/7.9/11+1 5/7 không phải 15 phần 7
I)19/5.2007/2017+19/5.10/2017
K) 4/25.5/9+-4/25.10/3+7/9
m) 7/19.8/11+7/19.3/11+12/19
n)17/13.18/23-4/13.18/23-(-5)/23
P) 5/7 .5/11+5/7.2/11-5/7.14/11
q)-2/17+15/19+-15/17+13/20+4/19
X)7/-25+-18/25+4/23+5/8+19/23
S)5/7.-4/19+-15/7.5/19
B1: Bỏ ngoặc rồi thực hiện phép tính (phân số)
a) (-5/11) - (7/19 - 5/31)
b) - ( 11/14 - 8/19) + (3/14 - 8/19)
B2: Tím số nguyên x, biết
-5/24 - 1/3 < x/24 < -1/8 + 1/3
A= 7/19.8/11+7/19.3/11+12/19
\(A=\dfrac{7}{19}\cdot\dfrac{8}{11}+\dfrac{7}{19}\cdot\dfrac{3}{11}+\dfrac{12}{19}\\ A=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)+\dfrac{12}{19}\\ A=\dfrac{7}{19}\cdot1+\dfrac{12}{19}\\ A=\dfrac{19}{19}=1\)
A = 7/19.8/11+7/19.3/11+12/19
A = 7/19. . (8/11 + 3/11) + 12/19
A = 7/19 . 1 + 12/19
A = 7/19 + 12/19
A = 1
Ta có: \(A=\dfrac{7}{19}\cdot\dfrac{8}{11}+\dfrac{7}{19}\cdot\dfrac{3}{11}+\dfrac{12}{19}\)
\(=\dfrac{7}{19}\cdot\left(\dfrac{8}{11}+\dfrac{3}{11}\right)+\dfrac{12}{19}\)
\(=\dfrac{7}{19}+\dfrac{12}{19}=1\)
\(\frac{5}{\frac{\frac{19}{3}}{19}-}-\frac{5}{\frac{14}{\frac{3}{14}+\frac{3}{11}}}+\frac{5}{11}\)
bài 1 tính
a) (3/7+-9/8)+(5/8+-6/14)
b) (-5/7+3/11)+(-11/14+14/-11)
c)(-4/5+2/3)+(-5/4+19/5)+(7/3.2)
d)9/16.13/4-9/4.5/16+9/16.17/4
-7/11.1+/19+-7/19.8/11-4/11
Đưa thừa số chung ra ngoài a, 5/7 . 5/11 + 5/7 . 2/11 - 5/7 . 14/11 b, 19 5/8 : 7/12 - 15 1/4 : 7/12 c, 2/5 . 1/3 - 2/15 : 1/5 + 3/5 . 1/3 d, 4/9 . 19 1/3 - 4/9 . 39 1/3
a: \(=\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\dfrac{-7}{11}=-\dfrac{5}{11}\)
b: \(=\dfrac{12}{7}\left(19+\dfrac{5}{8}-15-\dfrac{1}{4}\right)=\dfrac{12}{7}\cdot\left(4+\dfrac{3}{8}\right)\)
\(=\dfrac{12}{7}\cdot\dfrac{35}{8}=\dfrac{3}{2}\cdot5=\dfrac{15}{2}\)
c: \(=\dfrac{2}{15}-\dfrac{2}{15}\cdot5+\dfrac{3}{15}=\dfrac{2}{15}\cdot\left(-4\right)+\dfrac{3}{15}=\dfrac{-8+3}{15}=\dfrac{-5}{15}=-\dfrac{1}{3}\)
d: \(=\dfrac{4}{9}\left(19+\dfrac{1}{3}-39-\dfrac{1}{3}\right)=\dfrac{4}{9}\cdot\left(-20\right)=-\dfrac{80}{9}\)