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15 tháng 2 2023

a) \(\dfrac{5}{6}-\dfrac{2}{14}\)

\(=\dfrac{5}{6}-\dfrac{1}{7}\)

\(=\dfrac{35}{42}-\dfrac{6}{42}\)

\(=\dfrac{29}{42}\)

b) \(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{3}{12}-\dfrac{2}{12}\)

\(=\dfrac{1}{12}\)

c) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\)

d) \(8-\dfrac{4}{6}\)

\(=\dfrac{48}{6}-\dfrac{4}{6}\)

\(=\dfrac{44}{6}=\dfrac{22}{3}\).

5 tháng 3 2023

A) \(\dfrac{5}{10}-\dfrac{2}{15}\)

\(=\dfrac{1}{2}-\dfrac{2}{15}\)

\(=\dfrac{15}{30}-\dfrac{4}{30}\)

\(=\dfrac{11}{30}\)

B)\(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{6}{24}-\dfrac{4}{24}\)

\(=\dfrac{2}{24}=\dfrac{1}{12}\)

C) \(\dfrac{6}{18}-\dfrac{6}{24}\)

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

\(=\dfrac{4}{12}-\dfrac{3}{12}\)

\(=\dfrac{1}{12}\)

D) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\).

a: =1/2-2/15

=15/30-4/30

=11/30

b: =1/4-1/6

=3/12-2/12

=1/12

c: =1/3-1/4

=1/12

d: =20/36-9/36

=11/36

27 tháng 2 2019

A) \(\frac{7}{8}-\frac{5}{12}=\frac{84}{96}-\frac{40}{96}=\frac{44}{96}=\frac{11}{24}\)

B)\(\frac{8}{15}-\frac{2}{5}=\frac{8}{15}-\frac{6}{15}=\frac{2}{15}\)

C)\(\frac{5}{6}-\frac{3}{10}=\frac{50}{60}-\frac{18}{60}=\frac{32}{60}=\frac{8}{15}\)

D)\(\frac{7}{10}-\frac{1}{5}=\frac{7}{10}-\frac{2}{10}=\frac{5}{10}=\frac{1}{2}\)

2)A)\(\frac{5}{10}-\frac{2}{15}=\frac{1}{2}-\frac{2}{15}=\frac{15}{30}-\frac{4}{30}=\frac{11}{30}\)

B)\(\frac{5}{20}-\frac{1}{6}=\frac{1}{4}-\frac{1}{6}=\frac{6}{24}-\frac{4}{24}=\frac{2}{24}=\frac{1}{12}\)

C)\(\frac{6}{18}-\frac{6}{24}=\frac{1}{3}-\frac{1}{4}=\frac{4}{12}-\frac{3}{12}=\frac{1}{12}\)

D)\(\frac{5}{9}-\frac{3}{12}=\frac{5}{9}-\frac{1}{4}=\frac{20}{36}-\frac{9}{36}=\frac{11}{36}\)

Chúc bạn học tốt

18 tháng 2 2022

1.

a, Ta có 28=14⇒14+56=1312(Bn tự quy đồng lên nhé !)

b,Ta có1216=34⇒18+34=78(Bn tự quy đồng lên nhé !)

c,Ta có636=16⇒14+16=512(Bn tự quy đồng lên nhé !)

d,Ta có1218=23⇒23+14=1112(Bn tự quy đồng lên nhé !)

7.Phần này mk chỉ cho đáp án thuia.67     ;     

 b,420=15     ;         

c,615       ;            

d,129

25 tháng 7 2018

12/18 + 12/42 = 2/3 + 2/7 = 14/21 + 6/21 = 20/21

1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12

= 1/2 + 1/2 + 1/2 + 1/2 + 1/2 + 1/2

= 1/2 x 6

=6/2

=3

25 tháng 7 2018

Còn phần D thì sao😶

24 tháng 8 2023

a) \(\dfrac{2}{3}-\dfrac{2}{6}=\dfrac{4}{6}-\dfrac{2}{6}=\dfrac{4-2}{6}=\dfrac{2}{6}=\dfrac{1}{3}\)

b) \(\dfrac{5}{6}-\dfrac{3}{18}=\dfrac{10}{18}-\dfrac{3}{18}=\dfrac{10-3}{18}=\dfrac{7}{18}\)

c) \(\dfrac{8}{14}-\dfrac{2}{7}=\dfrac{8}{14}-\dfrac{4}{14}=\dfrac{8-4}{14}=\dfrac{4}{14}=\dfrac{2}{7}\)

d) \(\dfrac{12}{20}-\dfrac{2}{5}=\dfrac{12}{20}-\dfrac{8}{20}=\dfrac{12-8}{20}=\dfrac{4}{20}=\dfrac{1}{5}\)

28 tháng 10 2023

a: \(\dfrac{1}{8}+\dfrac{5}{8}=\dfrac{1+5}{8}=\dfrac{6}{8}=\dfrac{3}{4}\)

b: \(\dfrac{1}{15}+\dfrac{4}{15}=\dfrac{1+4}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)

c: \(\dfrac{5}{9}+\dfrac{7}{9}=\dfrac{5+7}{9}=\dfrac{12}{9}=\dfrac{4}{3}\)

d: \(\dfrac{23}{100}+\dfrac{27}{100}=\dfrac{23+27}{100}=\dfrac{50}{100}=\dfrac{1}{2}\)

4 tháng 2

a) 18+58=1+58=68=34

b) 115+415=1+415=515=13

c) 59+79=5+79=129=43

d) 

Bài 2:

a: 2/6x5/3=10/18=5/9

b: 11/9x5/10=55/90=11/18

c: 3/9x6/8=1/3x3/4=1/4

d: 4/9x12/16=48/144=1/3

e: 25/15x6/7=5/3x6/7=30/21=10/7

f: 6/10x15/20=90/200=9/20

27 tháng 2 2022

Bài 1

4/5 x 6/7= 24/35

2/9 x 1/2= 2/18= 1/9

1/2 x 8/3= 8/6= 4/3

7/9 x 6/5= 42/45= 14/15

8/7 x 5/9= 40/63

10/11 x 22/15= 220/165= 4/3

Bài 2

2/6 x 5/3= 1/3 x 5/3=5/9

11/9 x 5/10= 11/9 x 1/2= 11/18

3/9 x 6/8= 1/3 x 3/4 =3/12= 1/4

4/9 x 12/16= 4/9 x 3/4= 12/36= 1/3

25/15 x 6/7= 5/3 x 6/7= 30/21= 10/7

6/10 x 15/20= 3/5 x 3/4= 9/20

a: =8/5-2/3=24/15-10/15=14/15

12/20-6/18=3/5-1/3=9/15-5/15=4/15

b: 18/21-12/27=6/7-7/9=54/63-49/63=5/63

8/12-20/50=2/3-2/5=10/15-6/15=4/15

4 tháng 3 2022

\(a,\dfrac{8}{5}-\dfrac{18}{27}=\dfrac{8}{5}-\dfrac{2}{3}=\dfrac{14}{15}\\ \dfrac{12}{20}-\dfrac{6}{18}=\dfrac{3}{5}-\dfrac{1}{3}=\dfrac{4}{15}\\ b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\\ \dfrac{8}{12}-\dfrac{20}{50}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{4}{15}\)

27 tháng 2 2019

a, 5/10 - 2/15 = 1/2 - 2/15 = 15/30 - 4/30 = 11/30

b,5/20 - 1/6 = 1/4 - 1/6 = 3/12 - 2/12 = 1/12

c,6/18 - 6/24 = 1/3 - 1/4 = 4/12 - 3/12 = 1/12 

d,5/9 - 3/12 = 5/9 - 1/4 = 20/36 - 9/36 = 11/36 

27 tháng 2 2019

a:11/15

b:1/12

c:5/12

d:11/36