Bài này khó vãi . Sao ở trong phép tính còn có tiếng anh nữa .

a) \(\dfrac{-5}{9}-\dfrac{4}{15}+\dfrac{2}{9}-\dfrac{11}{15}\)

\(=\left(\dfrac{-5}{9}+\dfrac{2}{9}\right)-\left(\dfrac{4}{15}+\dfrac{11}{15}\right)\)

\(=\dfrac{-3}{9}-\dfrac{15}{15}\)

\(=-\dfrac{1}{3}-1\)

\(=-\dfrac{4}{3}\)

b) \(\dfrac{-8}{13}-\dfrac{7}{16}+\dfrac{21}{13}-\dfrac{1}{6}\)

\(=\left(\dfrac{-8}{13}+\dfrac{21}{13}\right)-\dfrac{7}{16}-\dfrac{1}{6}\)

\(=\dfrac{13}{13}-\dfrac{29}{48}\)

\(=1-\dfrac{29}{48}\)

\(=\dfrac{19}{48}\)

c) \(\dfrac{-15}{25}-\dfrac{14}{21}+\dfrac{8}{5}-\dfrac{5}{3}\)

\(=\dfrac{-3}{5}-\dfrac{2}{3}+\dfrac{8}{5}-\dfrac{5}{3}\)

\(=\left(\dfrac{-3}{5}+\dfrac{8}{5}\right)-\left(\dfrac{2}{3}+\dfrac{5}{3}\right)\)

\(=\dfrac{5}{5}-\dfrac{7}{3}\)

\(=1-\dfrac{7}{3}\)

\(=-\dfrac{4}{3}\)

a: =-5/9+2/9-11/15-4/15

=-3/9-1

=-12/9=-4/3

b: =-8/13+21/13-7/16-1/6

=1-1/6-7/16

=5/6-7/16

=19/48

c: =-15/25+8/5-2/3-5/3

=-7/3+1

=-4/3

\(\dfrac{25^5+25^7+25^9}{5^{11}+5^{13}+5^{15}+5^{17}+5^{19}+5^{21}}\)

\(=\dfrac{5^{10}+5^{14}+5^{18}}{5^{11}+5^{13}+5^{17}+5^{19}+5^{21}}\)

\(=\dfrac{5^{10}\left(1+5^4+5^8\right)}{5^{11}\left(1+5^2+5^4+5^6+5^8+5^{10}\right)}\)

\(=\dfrac{1+5^4+5^8}{5+5^3+5^5+5^7+5^9+5^{11}}\)

\(=\dfrac{1+5^4+5^8}{\left(5+5^5+5^9\right)+\left(5^3+5^7+5^{11}\right)}\)

\(=\dfrac{1+5^4+5^8}{\left(1+5^4+5^8\right)\left(5+5^3\right)}\)

\(=\dfrac{1}{5+5^3}\)

\(=\dfrac{1}{130}\)

\(\)

2. Tính (+5) + ( +4) = 9

3.Tính (- 9) + ( - 1) = -10

4.Tính : 28 + (-15) = 13

5.Tính (-15) + 12 = - 3

6.Tính (-25) + 25 = 0

7.Tính : 13 - 17 = - 4

8.Tính : (-78) - 9 = - 87

9.Tính : ( -24) - ( - 16) = - 8

10.Tính : 17 - (-3) = 20

11.Tính nhanh : (-21) - ( 48 + 52 - 21) = -100

2,  (+5)+(+4)=+9 hoạc 9 cũng được

3,  (-9)+(-1)=-10

4,  28+(-15)=13

5,  (-15)+12=-3

6,  (-25)+25=0

7,  13-17=4

8,   (-78)-9=-87

9,  (-24)-(-16)=-40

10, 17-(-3)=20

11,  (-21+21)-(48-52)=-4

ai mần tr mình cho tick

1: \(=\dfrac{272-168+186}{30}\cdot\dfrac{7}{9}=\dfrac{29}{3}\cdot\dfrac{7}{9}=\dfrac{203}{27}\)

2: \(=\dfrac{9-55}{33}\cdot\dfrac{6-5}{8}-\dfrac{4}{5}\cdot\dfrac{1}{24}=\dfrac{-4}{3}\cdot\dfrac{1}{8}-\dfrac{1}{30}=\dfrac{-1}{6}-\dfrac{1}{30}=\dfrac{-6}{30}=-\dfrac{1}{5}\)

3: \(=\dfrac{7}{3}\left(\dfrac{6}{25}+\dfrac{19}{25}\right)=\dfrac{7}{3}\cdot1=\dfrac{7}{3}\)

a) 35

b) -53

c) 40 –  - 7 2  = 40 – 49 = -9

d)| -15 + 21| - | 4 – 11 | = | 6 | - | -7 | = 6 – 7 = -1

12 mình chịu

11/15 + 8/5=                   Tính phân số

6/7 - 5/21=

25/4 x 16/100

7 x 2/49 =

4/3 : 2/9

5/8 : 25 =