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5 tháng 8 2018

a.  2 3 − 3 8 = 16 24 − 9 24 = 7 24

b.  2 3 × 9 5 = 2 × 9 3 × 5 = 18 15 = 6 5

6 tháng 5 2022

a) 3/7 + 3/4 - 1/2 =33/28-1/2=19/28

b) 6/11 + 2/9 x 12 =6/11+8/3=106/33

c) 5/7 - 8/5 : 4 =5/7-2/5=11/35

6 tháng 5 2022

a) 3/7 + 3/4 - 1/2 = \(\dfrac{12}{28}+\dfrac{21}{28}-\dfrac{14}{28}=\dfrac{19}{28}\)

b) 6/11 + 2/9 x 12 = \(\dfrac{6}{11}+\dfrac{8}{3}=\dfrac{18}{33}+\dfrac{88}{33}=\dfrac{106}{33}\)

c) 5/7 - 8/5 : 4 = \(\dfrac{5}{7}-\dfrac{2}{5}=\dfrac{25}{35}-\dfrac{14}{35}=\dfrac{11}{35}\)

25 tháng 3 2022

Cần chi tiết hum bẹn

25 tháng 3 2022

có nha

5 tháng 2 2022

\(\dfrac{53}{84}\)

\(\dfrac{20}{63}\)

\(\dfrac{1}{60}\)

a: \(\dfrac{2}{3}+\dfrac{5}{7}-\dfrac{3}{4}=\dfrac{56}{84}+\dfrac{60}{84}-\dfrac{63}{84}=\dfrac{53}{84}\)

b: \(=\dfrac{3}{7}-\dfrac{1}{9}=\dfrac{27}{63}-\dfrac{7}{63}=\dfrac{20}{63}\)

c: \(=\dfrac{2}{5}\cdot\dfrac{1}{8}\cdot\dfrac{1}{3}=\dfrac{2}{8}\cdot\dfrac{1}{15}=\dfrac{1}{60}\)

20 tháng 4 2022

87/56

2/3

24/25

28

20 tháng 4 2022

87/56

2/3

24/25

28

a: =2/5+3/5=1

b: =1/3+2/3=1

c: =7/8+5/8=12/8=3/2

d: =2/7+3/7=5/7

\(a,\dfrac{2}{5}+\dfrac{3}{5}=\dfrac{5}{5}=1\\ b,\dfrac{1}{3}+\dfrac{2}{3}=\dfrac{3}{3}=1\\ c,\dfrac{7}{8}+\dfrac{5}{8}=\dfrac{12}{8}=\dfrac{3}{2}\\ d,\dfrac{1}{7}+\dfrac{3}{7}=\dfrac{4}{7}\)

29 tháng 4 2022

a, \(1+\dfrac{3}{4}=\dfrac{7}{4}\)

b, \(\dfrac{4}{5}-\dfrac{3}{8}=\dfrac{32-15}{40}=\dfrac{17}{40}\)

c, \(1:\dfrac{2}{3}=\dfrac{1.3}{2}=\dfrac{3}{2}\)

d, \(\dfrac{2}{5}.\dfrac{5}{2}=1\)

29 tháng 4 2022

a)1 + 3/4=7/4

   b)4/5 -3/8=17/40

  c)1 : 2/3=3/2

  d)2/5 x 5/2=1

8 tháng 3 2023

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\(a,\dfrac{4}{7}+\dfrac{7}{2}\\ =\dfrac{8}{14}+\dfrac{49}{14}\\ =\dfrac{8+49}{14}\\ =\dfrac{57}{14}\)

\(b,\dfrac{5}{8}\times\dfrac{3}{2}\\ =\dfrac{5\times3}{8\times2}\\ =\dfrac{15}{16}\)

\(c,\dfrac{3}{2}\times\dfrac{5}{6}-\dfrac{2}{3}\\ =\dfrac{3\times5}{2\times6}-\dfrac{2}{3}\\ =\dfrac{15}{12}-\dfrac{2}{3}\\ =\dfrac{15}{12}-\dfrac{8}{12}\\ =\dfrac{15-8}{12}\\ =\dfrac{7}{12}\)

\(d,\dfrac{13}{15}+\dfrac{2}{5}:\dfrac{3}{4}\\ =\dfrac{13}{15}+\dfrac{2}{5}\times\dfrac{4}{3}\\ =\dfrac{13}{15}+\dfrac{2\times4}{5\times3}\\ =\dfrac{13}{15}+\dfrac{8}{15}\\ =\dfrac{13+8}{15}\\ =\dfrac{21}{15}\\ =\dfrac{7}{5}\)

a: 4/9+3/7=28/63+27/63=55/63

3/4+7/24=18/24+7/24=25/24

1/3+2/9+4/27=9/27+6/27+4/27=19/27

b: 5/6-3/8=20/24-9/24=11/24

7/15-11/30=14/30-11/30=3/30=1/10

2/3+1/6-7/12

=8/12+2/12-7/12

=3/12=1/4

c: 18/25*15/6=15/25*18/6=3*3/5=9/5

30/49:6/7=30/49*7/6=210/294=5/7

1/2*3/4:6/5=3/8*5/6=15/48=5/16

d: 8*3/5:12/5=24/5*5/12=2

4:9/5:10/3=4*5/9*3/10=2/3

27 tháng 2 2023

`a,2/5 + 3/4`

`= 8/20 + 15/20`

`= 23/20`

`b,2/7 + 5/9`

`= 18/63 + 35/63`

`= 53/63`

`c, 4/7 + 3/4 + 2/7`

`= ( 4/7 + 2/7)+3/4`

`= 6/7 + 3/4`

`= 24/28 + 21/28`

`= 45/28`

`@ yl`

27 tháng 2 2023

\(\dfrac{2}{5}+\dfrac{3}{4}=\dfrac{8}{20}+\dfrac{15}{20}=\dfrac{23}{20}\)

\(\dfrac{2}{7}+\dfrac{5}{9}=\dfrac{18}{63}+\dfrac{35}{63}=\dfrac{53}{63}\)

\(\dfrac{4}{7}+\dfrac{3}{4}+\dfrac{2}{7}= \left(\dfrac{4}{7}+\dfrac{2}{7}\right)+\dfrac{3}{4}=\dfrac{6}{7}+\dfrac{3}{4}=\dfrac{45}{28}\)