17/11 - ( 9/4 - 9/5 ) - ( 5/4 + 6/7)
a) -5/11 + ( -6/11 + 1 )
b) -13/17 + ( 13/-21 + -4/17 )
c) -5/12 . 7/-17 . 9/-20
d) 13/17 . 4/-5 + 13/17 . -3/4
e) -5/7 . 2/11 + -5/7 . 9/11 + 5/7
f) -2/5 . (-6) + 3/4 . 4/-10
a: =-5/11-6/11+1=-11/11+1=0
b: =-13/17-13/21-4/17=-1-13/21=-34/21
b: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=\dfrac{-21}{272}\)
d: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{13}{17}\cdot\dfrac{-31}{20}=\dfrac{-403}{340}\)
a) -5/12 . 7/-17 . 9/-20
b) 13/17 . 4/-5 + 13/17 . -3/4
c)-5/7 . 2/11 + -5/7 . 9/11 + 5/7
d)-2/5 . (-6) + 3/4 . 4/-10
a: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=-\dfrac{21}{272}\)
b: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{-13}{17}\cdot\dfrac{31}{20}=-\dfrac{403}{340}\)
c: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{5}{7}=-\dfrac{5}{7}+\dfrac{5}{7}=0\)
d: \(=\dfrac{12}{5}-\dfrac{3}{10}=\dfrac{21}{10}\)
bài 1:
a,1/10*2/9*3/8*4/7*5/6*6/5*7/4*8/3*9/2
b,8/11+4/17-5/11-3/17-65/9-8/17-3/17-6/17
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
Tính hợp lý
A=A=7/4*5-9/4*5+11/5*6-11/6*7+13/7*8-15/8*9+17/9*10-19/10*11
Tính: 7/3*4-9/4*5+11/5*6-13/6*7+15/7*8-17/8*9+19/9*10
F=7/(3*4)-9/(4*5)+11/(5*6)-13/)6*7)+15/(7*8)-17/(8*9)+19/(9*10)
a) 5/7 + 4/3 + 2/7 + 5/3
b) 17/12 + 29/7 - 8/7 + 7/12
c) 2/5 + 6/9 + 7/4 + 3/5 + 1/3 + 1/4
d) 17/51 + 13/17 + 29/11 + 50/75 + 4/17 + 4/11
a: =(5/7+2/7)+(4/3+5/3)=3+1=4
b: =(17/12+7/12)+(29/7-8/7)
=2+3=5
c: =(2/5+3/5)+(6/9+1/3)+(7/4+1/4)
=1+2+1
=4
d: =(1/3+2/3)+(13/17+4/17)+(29/11+4/11)
=1+1+3=5
Tính nhẩm:
a)
7 + 5 = ..... 5 + 7 = .....
4 + 9 = ..... 9 + 4 = .....
8 + 7 = ..... 7 + 8 = .....
2 + 9 = ..... 9 + 2 = .....
b)
16 − 8 = ..... 14 − 7 = .....
11 − 9 = ..... 17 − 9 = .....
12 − 5 = ..... 16 − 9 = .....
13 − 6 = ..... 15 − 8 = .....
Phương pháp giải:
Tính nhẩm rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
a)
7 + 5 = 12 5 + 7 = 12
4 + 9 = 13 9 + 4 = 13
8 + 7 = 15 7 + 8 = 15
2 + 9 = 11 9 + 2 = 11
b)
16 − 8 = 8 14 − 7 = 7
11 − 9 = 2 17 − 9 = 8
12 − 5 = 7 16 − 9 = 7
13 − 6 = 7 15 − 8 = 7
7+5=17 5+7=17
4+9=13 9+4=13
a) 1/2 - 5/6 + 11/33 - 35/40
b) 2/3 . 1 3/4 - 8/9 - 17/51 - 1/5
c) 1/2 . 2 - 2 5/7 + 6/4 - 10/15
d) 1/6 . 1/11 + 4/11 . ( -1/6) + 8/11 . 1/6 + 1/6 . 6/11
e) -17 . (-23) + (-53) . 17 +17 . 14 + 17 .(-24)
f) -19,218 + (-82) .19 - 533 . 19 + (-19) . 167
g) 2/5 + 3/8 - 11/44 + 9/16
h) 4/10 - 1 5/6 . 2 + 7/8 -1/9
i ) 3. 1/5 - 2/8 - 12/36 + 15/9
k) 6/8 . 3 1/2 + 4 2/3 - 11/55 + 17/51
l ) 1/3 . 3 1/2 - 4 2/5 - 26/78 + 17/51
`@` `\text {Ans}`
`\downarrow`
`a)`
\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{11}{33}-\dfrac{35}{40}\)
`=`\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{1}{3}-\dfrac{7}{8}\)
`=`\(\dfrac{12}{24}-\dfrac{20}{24}+\dfrac{8}{24}-\dfrac{21}{24}\)
`= -21/24 = -7/8`
`b)`
\(\dfrac{2}{3}\cdot1\dfrac{3}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)
`=`\(\dfrac{2}{3}\cdot\dfrac{7}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)
`=`\(\dfrac{7}{6}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)
`=`\(\dfrac{5}{18}-\dfrac{17}{51}-\dfrac{1}{5}\)
`=`\(-\dfrac{1}{18}-\dfrac{1}{5}=-\dfrac{23}{90}\)
`c)`
\(\dfrac{1}{2}\cdot2-2\dfrac{5}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)
`=`\(1-\dfrac{19}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)
`=`\(-\dfrac{12}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)
`=`\(-\dfrac{3}{14}-\dfrac{10}{15}=-\dfrac{37}{42}\)
`d) `
\(\dfrac{1}{6}\cdot\dfrac{1}{11}+\dfrac{4}{11}\cdot\left(-\dfrac{1}{6}\right)+\dfrac{8}{11}\cdot\dfrac{1}{6}+\dfrac{1}{6}\cdot\dfrac{6}{11}\)
`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1}{11}-\dfrac{4}{11}+\dfrac{8}{11}+\dfrac{6}{11}\right)\)
`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1-4+8+6}{11}\right)\)
`=`\(\dfrac{1}{6}\cdot1=\dfrac{1}{6}\)
`e)`
\(-17\cdot\left(-23\right)+\left(-53\right)\cdot17+17\cdot14+17\cdot\left(-24\right)\)
`= 17*(23-53+14-24)`
`= 17*(-40)`
`= -680`
`f)`
\(-19\cdot218+\left(-82\right)\cdot19-533\cdot19+\left(-19\right)\cdot167\)
`= 19*(-218-82-533-167)`
`= 19*(-1000)`
`= -19000`
`g)`
\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{11}{44}+\dfrac{9}{16}\)
`=`\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{1}{4}+\dfrac{9}{16}\)
`=`\(\dfrac{31}{40}-\dfrac{1}{4}+\dfrac{9}{16}\)
`=`\(\dfrac{21}{40}+\dfrac{9}{16}=\dfrac{87}{80}\)
`h)`
\(\dfrac{4}{10}-1\dfrac{5}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)
`=`\(\dfrac{4}{10}-\dfrac{11}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)
`=`\(\dfrac{4}{10}-\dfrac{11}{3}+\dfrac{7}{8}-\dfrac{1}{9}\)
`=`\(-\dfrac{49}{15}+\dfrac{7}{8}-\dfrac{1}{9}\)
`=`\(-\dfrac{287}{120}-\dfrac{1}{9}=-\dfrac{901}{360}\)
`i )`
\(3\cdot\dfrac{1}{5}-\dfrac{2}{8}-\dfrac{12}{36}+\dfrac{15}{9}\)
`=`\(\dfrac{3}{5}-\dfrac{1}{4}-\dfrac{1}{3}+\dfrac{15}{9}\)
`=`\(\dfrac{7}{20}-\dfrac{1}{3}+\dfrac{15}{9}\)
`=`\(\dfrac{1}{60}+\dfrac{15}{9}=-\dfrac{33}{20}\)
`k)`
\(\dfrac{6}{8}\cdot3\dfrac{1}{2}+4\dfrac{2}{3}-\dfrac{11}{55}+\dfrac{17}{51}\)
`=`\(\dfrac{3}{4}\cdot\dfrac{7}{2}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)
`=`\(\dfrac{21}{8}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)
`=`\(\dfrac{175}{24}-\dfrac{1}{5}+\dfrac{17}{51}\)
`=`\(\dfrac{851}{120}+\dfrac{17}{51}=\dfrac{297}{40}\)
`l )`
\(\dfrac{1}{3}\cdot3\dfrac{1}{2}-4\dfrac{2}{5}-\dfrac{26}{78}+\dfrac{17}{51}\)
`=`\(\dfrac{1}{3}\cdot\dfrac{7}{2}-\dfrac{22}{5}-\dfrac{1}{3}+\dfrac{17}{51}\)
`=`\(\dfrac{1}{3}\left(\dfrac{7}{2}-1\right)-\dfrac{22}{5}+\dfrac{17}{51}\)
`=`\(\dfrac{1}{3}\cdot\dfrac{5}{2}-\dfrac{22}{5}+\dfrac{17}{51}\)
`=`\(\dfrac{5}{6}-\dfrac{22}{5}+\dfrac{17}{51}\)
`=`\(-\dfrac{107}{30}+\dfrac{17}{51}=-\dfrac{97}{30}\)
P/s: Bạn tách bài ra hỏi nhé! Và ghi đề rõ ràng chứ đừng ghi ntnay, nhiều bạn nhìn vào rất khó nhìn!
`# \text {KaizulvG}`
a)
` 1/2 - 5/6 + 11/33 - 35/40 `
`= 1/2 - 5/6 + 1/3 - 7/8 `
`= ( 1/2 - 5/6 ) + ( 1/3 - 7/8 ) `
`= ( 3/6 - 5/6 ) + ( 8/24 - 21/24 ) `
`= -2/6 + (-13)/24 `
`= -1/3 + (-13)/24 `
`= -8/24 + (-13)/24 `
`= -21/24 = -7/8 `