a.\(\dfrac{27}{8}\)

b.\(\dfrac{37}{40}\)
c.\(\dfrac{5}{2}\)

d.\(\dfrac{7}{3}\)

e.5

g.\(\dfrac{53}{16}\)

Bài 1 :

a) \(\dfrac{3}{2}+\dfrac{5}{4}+\dfrac{5}{8}=\dfrac{12}{8}+\dfrac{10}{8}+\dfrac{5}{8}=\dfrac{12+10+5}{8}=\dfrac{27}{8}\)

b) \(\dfrac{4}{5}-\dfrac{3}{8}+\dfrac{2}{4}=\dfrac{32}{40}-\dfrac{15}{40}+\dfrac{20}{40}=\dfrac{32-15+20}{40}=\dfrac{37}{40}\)

c) \(3+\dfrac{6}{8}-\dfrac{5}{4}=\dfrac{3}{1}+\dfrac{6}{8}-\dfrac{5}{4}=\dfrac{24}{8}+\dfrac{6}{8}-\dfrac{10}{8}=\dfrac{20}{8}=\dfrac{5}{2}\)

d) \(\dfrac{5}{6}-\dfrac{1}{2}+2=\dfrac{5}{6}-\dfrac{1}{2}+\dfrac{2}{1}=\dfrac{5}{6}-\dfrac{3}{6}+\dfrac{12}{6}=\dfrac{14}{6}=\dfrac{7}{3}\)

e) \(\dfrac{3}{5}+\dfrac{6}{11}+\dfrac{7}{13}+\dfrac{2}{5}+\dfrac{16}{11}+\dfrac{19}{13}=\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{6}{11}+\dfrac{16}{11}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)=1+2+2=5\)

g) \(\dfrac{75}{100}+\dfrac{18}{21}+\dfrac{29}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}=\dfrac{3}{4}+\dfrac{6}{7}+\dfrac{29}{32}+\dfrac{1}{4}+\dfrac{1}{7}+\dfrac{13}{32}=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{6}{7}+\dfrac{1}{7}\right)+\left(\dfrac{29}{32}+\dfrac{13}{32}\right)=1+1+\dfrac{21}{16}=2+\dfrac{21}{16}=\dfrac{53}{16}\)

a,3/2+5/4+5/8 = 12/8 + 10/8 + 5/8 = 27/8

b,4/5-3/8+2/4 = 32/40 - 15/40 + 20/40 = 37/40

c,3+6/8-5/4= 24/8 + 6/8 - 10/8 = 20/8 = 5/2

d,5/6-1/2+2 = 5/6 - 3/6 + 12/6 = 14/6 = 7/3

e,3/5+6/11+7/13+2/5+16/11+19/13 = ( 3/5+ 2/5) + ( 6/11 + 16/11) + ( 7/13 + 19/13) = 1 + 2 + 2 = 5

g,75/100+18/21+29/32+1/4+3/21+13/32 = 3/4 + 6/7 + 29/32 + 1/4 + 1/7 + 13/32=  ( 3/4 + 1/4) + ( 29/32 + 13/32) + ( 6/7 + 1/7)= 1 + 21/16 + 1 = 53/16

Cần chi tiết hum bẹn

a) = 76/35 ; 37/9

b) 143/40 ; 19/15

c) 2/3 ; 42/5

d) 21/4 ; 4/7 

a, 11/7 + 3/5

= \(\dfrac{11x5}{7x5}+\dfrac{3x7}{5x7}=\dfrac{55}{35}+\dfrac{21}{35}=\dfrac{76}{35}\)

4 + 1/9

= \(\dfrac{4}{1}+\dfrac{1}{9}=\dfrac{4x9}{1x9}+\dfrac{1x1}{9x1}=\dfrac{36}{9}+\dfrac{1}{9}=\dfrac{37}{9}\)

b, 21/5 - 5/8

= \(\dfrac{21x8}{5x8}-\dfrac{5x5}{8x5}=\dfrac{168}{40}-\dfrac{25}{40}=\dfrac{143}{40}\)

2 - 11/15

=\(\dfrac{2}{1}-\dfrac{11}{15}=\dfrac{30}{15}-\dfrac{11}{15}=\dfrac{19}{15}\)

MIK LÀM ĐC NGẦN ĐẤY THUI BẸN THÔNG CẢM

4:

a: =4/15-2,9+11/15=1-2,9=-1,9

b: \(=-36,75+3,7-63,25+6,3=10-100=-90\)

c: \(=6,5+3,5-\dfrac{10}{17}-\dfrac{7}{17}=10-1=9\)

d: \(=\dfrac{13}{25}\left(-39,1-60,9\right)=\dfrac{13}{25}\left(-100\right)=-52\)

e: =-5/12-7/12-3,7-6,3=-1-10=-11

f: =2,8(-6/13-7/13)-7,2=-2,8-7,2=-10

cậu tách ra từng bài thôi nha.

Ghi đầy đủ nha

bn có thể ghi rõ ràng đc ko?

a)\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{3}{7}\) 

=\(\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\dfrac{5}{13}\) 

=\(0+\dfrac{5}{13}\) 

=\(\dfrac{5}{13}\)

`@` `\text {Ans}`

`\downarrow`

`1,`

`a)`

`-7/25 + (-8)/25`

`= (-7 - 8)/25`

`= -15/25`

`= -3/5`

`b)`

`6/13 + (-15)/39`

`= 18/39 + (-15)/39`

`= (18 - 15)/39`

`= 3/39`

`= 1/13`

`c)`

`5/7 + 4/(-14)`

`= 10/14 + (-4)/14`

`= (10 - 4)/14`

`= 6/14`

`= 3/7`

`d)`

`-8/18 + (-15)/27`

`= -4/9 + (-5)/9`

`= (-4-5)/9`

`= -9/9 = -1`

`2,`

`a)`

`3/5 + (-7)/4`

`= 12/20 + (-35)/20`

`= (12 - 35)/20`

`=-23/20`

`b)`

`(-2) + (-5)/8`

`= (-16)/8 + (-5)/8`

`= (-16 - 5)/8`

`= -21/8`

`c)`

`1/8 + (-5)/9`

`= 9/72 + (-40)/72`

`= (9-40)/72`

`= -31/72`

`d)`

`6/13 + (-14)/39`

`= 18/39 + (-14)/39`

`= (18 - 14)/39`

`= 4/39`

`e)`

`(-18)/24 + 15/21`

`= (-3)/4 + 5/7`

`= (-21)/28 + 20/28`

`= (-21 + 20)/28`

`= -1/28`

`@` `\text {Ans}`

`\downarrow`

`1)`

`5/7*37 13/23 - 51 13/23*5/7`

`= 5/7* (37 13/23 - 51 13/23)`

`= 5/7* (-14)`

`= -10`

`2)`

`-2/3 +1/3+0,5+2 1/2`

`= -2/3 + 1/3 + 1/2 + 5/2`

`= (-2/3+1/3) + (1/2+5/2)`

`= -1/3 + 3`

`=8/3`

`3)`

`-0,5+2/3+1/2`

`= -1/2 + 2/3 + 1/2`

`= (-1/2 + 1/2) + 2/3`

`= 2/3`

`4)`

`(8+2 1/3-3/5) -(5+0,4)-(3 1/2 -2)`

`= 8+ 7/3 - 3/5 - 5 - 0,4 - 7/2 + 2`

`= (8+2-5) + (-3/5 - 2/5) + (7/3 - 7/2)`

`= 5 - 1 - 7/6`

`= 4 - 7/6 = 17/6`

`5)`

`(2/9-7/12):3/4+(16/9-5/12):3/4`

`= (2/9 - 7/12) \times 4/3 + (16/9 - 5/12) \times 4/3`

`= 4/3 *(2/9 - 7/12 + 16/9 - 5/12)`

`= 4/3 * [(2/9 + 16/9) + (-7/12 - 5/12)]`

`= 4/3 * ( 2 - 1)`

`= 4/3 * 1 = 4/3`

`6)`

`-(2021.0,7+19,75) +0,7- (8-19,75)`

`= -2021*0,7 -19,75 + 0,7 - 8 + 19,75`

`= 0,7*(-2021 + 1) - 8`

`= -1414-8`

`= -1422`

`7)`

`15/34+7/21+19/34-20/15`

`= (15/34 + 19/34) + 7/21 - 20/15`

`= 1 + 7/21 - 20/15`

`= 4/3 - 20/15 =0`

`8)`

`2 5/6+1/6:(-5/8)`

`= 17/6 + (-4/15)`

`= 77/30`

`9)`

`(-2)^2 +2/9. (4/5-2/3)`

`= 4 + 2/9*2/15`

`= 4+4/135`

`= 544/135`

`10)`

`(-1/5+3/7):5/4+(-4/5+4/7):5/4`

`= (-1/5+3/7) * 4/5 + (-4/5+4/7) * 4/5`

`= 4/5*(-1/5 +3/7-4/5+4/7)`

`= 4/5*[(-1/5-4/5)+(3/7+4/7)]`

`= 4/5* (-1+1)`

`= 4/5*0=0`

`11)`

`2022,2021 . 1954,1945+ 2022,2021 . (-1954,1945)`

`= 2022,2021 * [1954,1945 + (-1954,1945)]`

`= 2022,2021*0 `

`= 0`

`12)`

`-5,2 .72 +69,1 +5,2 . (-28)+(-1,1)`

`= -5,2*72 + 69,1 - 5,2*28 - 1,1`

`= -5,2*(72+28) + (69,1 - 1,1)`

`= -5,2*100 + 68`

`= -520 + 68`

`= -452`

`13)`

`(7 -1/2-3/4) : (5-1/4-5/8)`

`= 23/4 \div 33/8`

`=46/33`

`14)`

`(8+ 2 1/3 -3/5) -(5+0,4) -( 3 1/3 - 2)`

`= 8+ 2 1/3 - 3/5 - 5 - 0,4 - 3 1/3 + 2`

`= (8+2-5) + (2 1/3 - 3 1/3) - (0,6 + 0,4) `

`= 5 - 1 - 1`

`= 3`

help lười tính quá

2: \(=\dfrac{-1}{3}+3=\dfrac{8}{3}\)

3: =1/2-1/2+2/3=2/3

5: \(=\dfrac{4}{3}\left(\dfrac{2}{9}-\dfrac{7}{12}+\dfrac{16}{9}-\dfrac{5}{12}\right)=\dfrac{4}{3}\)

12: \(=5.2\left(-72-28\right)+68=-520+68=-452\)

13: \(\dfrac{23}{4}:\dfrac{33}{8}=\dfrac{46}{33}\)

`a)1 4/23 + ( 5/21-4/23)+16/21-1/2`

`=27/23+5/21-4/23+16/21-1/2`

`=(27/23-4/23)+(5/21+16/21)-1/2`

`=23/23+21/21-1/2`

`=1+1-1/2`

`=2-1/2`

`=4/2-1/2`

`=3/2`

___

`b)75%-(5/2+5/3)+(-1/2)^3`

`=3/4-5/2+5/3+(-1/8)`

`=(3/4-5/2-1/8)+5/3`

`=(6/8-20/8-1/8)+5/3`

`=-15/8+5/3`

`=-45/24+40/24`

`=-5/24`

___

`c)-3/4(-55/9).8/11`

`=-3/4.(-40/9)`

`=-10/3`

__

`d)-3/8 . 6/13 + 7/13 . (-3/8) + 1 3/8`

`= -3/8 . (6/13 + 7/13) + 11/8`

`= -3/8 . 13/13 + 11/8`

`= -3/8 .1 + 11/8`

`= -3/8 + 11/8`

`= 8/8`

`=1`

a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)

\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)

\(=\dfrac{-1621}{126}\)

b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

b: \(27D=3^{14}+3^{17}+...+3^{2024}\)

\(\Leftrightarrow26D=3^{2024}-3^{11}\)

hay \(D=\dfrac{3^{2024}-3^{11}}{26}\)

c: \(25E=-5^4-5^6-...-5^{1002}\)

\(\Leftrightarrow24E=-5^{1002}+5^2\)

hay \(E=\dfrac{-5^{1002}+5^2}{24}\)